Appendix E to Subpart M of Part 1926 - Sample Fall Protection Plan
29:8.1.1.1.1.13.19.5.10 : Appendix E
Appendix E to Subpart M of Part 1926 - Sample Fall Protection Plan
Non-Mandatory Guidelines for Complying With § 1926.502(k)
Employers engaged in leading edge work, precast concrete
construction work and residential construction work who can
demonstrate that it is infeasible or creates a greater hazard to
use conventional fall protection systems must develop and follow a
fall protection plan. Below are sample fall protection plans
developed for precast concrete construction and residential work
that could be tailored to be site specific for other precast
concrete or residential jobsite. This sample plan can be modified
to be used for other work involving leading edge work. The sample
plan outlines the elements that must be addressed in any fall
protection plan. The reasons outlined in this sample fall
protection plan are for illustrative purposes only and are not
necessarily a valid, acceptable rationale (unless the conditions at
the job site are the same as those covered by these sample plans)
for not using conventional fall protection systems for a particular
precast concrete or residential construction worksite. However, the
sample plans provide guidance to employers on the type of
information that is required to be discussed in fall protection
plans.
Sample Fall Protection Plans Fall Protection Plan For
Precast/Prestress Concrete Structures
This Fall Protection Plan is specific for the following
project:
Location of Job Erecting Company Date Plan Prepared or Modified
Plan Prepared By Plan Approved By Plan Supervised By
The following Fall Protection Plan is a sample program prepared
for the prevention of injuries associated with falls. A Fall
Protection Plan must be developed and evaluated on a site by site
basis. It is recommended that erectors discuss the written Fall
Protection Plan with their OSHA Area Office prior to going on a
jobsite.
I. Statement of Company Policy
(Company Name) is dedicated to the protection of its employees
from on-the-job injuries. All employees of (Company Name) have the
responsibility to work safely on the job. The purpose of this plan
is: (a) To supplement our standard safety policy by providing
safety standards specifically designed to cover fall protection on
this job and; (b) to ensure that each employee is trained and made
aware of the safety provisions which are to be implemented by this
plan prior to the start of erection.
This Fall Protection Plan addresses the use of other than
conventional fall protection at a number of areas on the project,
as well as identifying specific activities that require
non-conventional means of fall protection. These areas include:
a. Connecting activity (point of erection).
b. Leading edge work.
c. Unprotected sides or edge.
d. Grouting.
This plan is designed to enable employers and employees to
recognize the fall hazards on this job and to establish the
procedures that are to be followed in order to prevent falls to
lower levels or through holes and openings in walking/working
surfaces. Each employee will be trained in these procedures and
strictly adhere to them except when doing so would expose the
employee to a greater hazard. If, in the employee's opinion, this
is the case, the employee is to notify the foreman of the concern
and the concern addressed before proceeding.
Safety policy and procedure on any one project cannot be
administered, implemented, monitored and enforced by any one
individual. The total objective of a safe, accident free work
environment can only be accomplished by a dedicated, concerted
effort by every individual involved with the project from
management down to the last employee. Each employee must understand
their value to the company; the costs of accidents, both monetary,
physical, and emotional; the objective of the safety policy and
procedures; the safety rules that apply to the safety policy and
procedures; and what their individual role is in administering,
implementing, monitoring, and compliance of their safety policy and
procedures. This allows for a more personal approach to compliance
through planning, training, understanding and cooperative effort,
rather than by strict enforcement. If for any reason an unsafe act
persists, strict enforcement will be implemented.
It is the responsibility of (name of competent person) to
implement this Fall Protection Plan. (Name of Competent Person) is
responsible for continual observational safety checks of their work
operations and to enforce the safety policy and procedures. The
foreman also is responsible to correct any unsafe acts or
conditions immediately. It is the responsibility of the employee to
understand and adhere to the procedures of this plan and to follow
the instructions of the foreman. It is also the responsibility of
the employee to bring to management's attention any unsafe or
hazardous conditions or acts that may cause injury to either
themselves or any other employees. Any changes to this Fall
Protection Plan must be approved by (name of Qualified Person).
II. Fall Protection Systems To Be Used on This Project
Where conventional fall protection is infeasible or creates a
greater hazard at the leading edge and during initial connecting
activity, we plan to do this work using a safety monitoring system
and expose only a minimum number of employees for the time
necessary to actually accomplish the job. The maximum number of
workers to be monitored by one safety monitor is six (6). We are
designating the following trained employees as designated erectors
and they are permitted to enter the controlled access zones and
work without the use of conventional fall protection.
Safety monitor: Designated erector: Designated erector: Designated
erector: Designated erector: Designated erector: Designated
erector:
The safety monitor shall be identified by wearing an orange hard
hat. The designated erectors will be identified by one of the
following methods:
1. They will wear a blue colored arm band, or
2. They will wear a blue colored hard hat, or
3. They will wear a blue colored vest.
Only individuals with the appropriate experience, skills, and
training will be authorized as designated erectors. All employees
that will be working as designated erectors under the safety
monitoring system shall have been trained and instructed in the
following areas:
1. Recognition of the fall hazards in the work area (at the
leading edge and when making initial connections - point of
erection).
2. Avoidance of fall hazards using established work practices
which have been made known to the employees.
3. Recognition of unsafe practices or working conditions that
could lead to a fall, such as windy conditions.
4. The function, use, and operation of safety monitoring
systems, guardrail systems, body belt/harness systems, control
zones and other protection to be used.
5. The correct procedure for erecting, maintaining,
disassembling and inspecting the system(s) to be used.
6. Knowledge of construction sequence or the erection plan.
A conference will take place prior to starting work involving
all members of the erection crew, crane crew and supervisors of any
other concerned contractors. This conference will be conducted by
the precast concrete erection supervisor in charge of the project.
During the pre-work conference, erection procedures and sequences
pertinent to this job will be thoroughly discussed and safety
practices to be used throughout the project will be specified.
Further, all personnel will be informed that the controlled access
zones are off limits to all personnel other than those designated
erectors specifically trained to work in that area.
Safety Monitoring System
A safety monitoring system means a fall protection system in
which a competent person is responsible for recognizing and warning
employees of fall hazards. The duties of the safety monitor are
to:
1. Warn by voice when approaching the open edge in an unsafe
manner.
2. Warn by voice if there is a dangerous situation developing
which cannot be seen by another person involved with product
placement, such as a member getting out of control.
3. Make the designated erectors aware they are in a dangerous
area.
4. Be competent in recognizing fall hazards.
5. Warn employees when they appear to be unaware of a fall
hazard or are acting in an unsafe manner.
6. Be on the same walking/working surface as the monitored
employees and within visual sighting distance of the monitored
employees.
7. Be close enough to communicate orally with the employees.
8. Not allow other responsibilities to encumber monitoring. If
the safety monitor becomes too encumbered with other
responsibilities, the monitor shall (1) stop the erection process;
and (2) turn over other responsibilities to a designated erector;
or (3) turn over the safety monitoring function to another
designated, competent person. The safety monitoring system shall
not be used when the wind is strong enough to cause loads with
large surface areas to swing out of radius, or result in loss of
control of the load, or when weather conditions cause the
walking-working surfaces to become icy or slippery.
Control Zone System
A controlled access zone means an area designated and clearly
marked, in which leading edge work may take place without the use
of guardrail, safety net or personal fall arrest systems to protect
the employees in the area. Control zone systems shall comply with
the following provisions:
1. When used to control access to areas where leading edge and
other operations are taking place the controlled access zone shall
be defined by a control line or by any other means that restricts
access.
When control lines are used, they shall be erected not less than
6 feet (l.8 m) nor more than 60 feet (18 m) or half the length of
the member being erected, whichever is less, from the leading
edge.
2. The control line shall extend along the entire length of the
unprotected or leading edge and shall be approximately parallel to
the unprotected or leading edge.
3. The control line shall be connected on each side to a
guardrail system or wall.
4. Control lines shall consist of ropes, wires, tapes, or
equivalent materials, and supporting stanchions as follows:
5. Each line shall be flagged or otherwise clearly marked at not
more than 6-foot (1.8 m) intervals with high- visibility
material.
6. Each line shall be rigged and supported in such a way that
its lowest point (including sag) is not less than 39 inches (1 m)
from the walking/working surface and its highest point is not more
than 45 inches (1.3 m) from the walking/working surface.
7. Each line shall have a minimum breaking strength of 200
pounds (.88 kN).
Holes
All openings greater than 12 in. × 12 in. will have perimeter
guarding or covering. All predetermined holes will have the plywood
covers made in the precasters' yard and shipped with the member to
the jobsite. Prior to cutting holes on the job, proper protection
for the hole must be provided to protect the workers. Perimeter
guarding or covers will not be removed without the approval of the
erection foreman.
Precast concrete column erection through the existing deck
requires that many holes be provided through this deck. These are
to be covered and protected. Except for the opening being currently
used to erect a column, all opening protection is to be left
undisturbed. The opening being uncovered to erect a column will
become part of the point of erection and will be addressed as part
of this Fall Protection Plan. This uncovering is to be done at the
erection foreman's direction and will only occur immediately prior
to “feeding” the column through the opening. Once the end of the
column is through the slab opening, there will no longer exist a
fall hazard at this location.
III. Implementation of Fall Protection Plan
The structure being erected is a multistory total precast
concrete building consisting of columns, beams, wall panels and
hollow core slabs and double tee floor and roof members.
The following is a list of the products and erection situations
on this job:
Columns
For columns 10 ft to 36 ft long, employees disconnecting crane
hooks from columns will work from a ladder and wear a body
belt/harness with lanyard and be tied off when both hands are
needed to disconnect. For tying off, a vertical lifeline will be
connected to the lifting eye at the top of the column, prior to
lifting, to be used with a manually operated or mobile rope grab.
For columns too high for the use of a ladder, 36 ft and higher, an
added cable will be used to reduce the height of the disconnecting
point so that a ladder can be used. This cable will be left in
place until a point in erection that it can be removed safely. In
some cases, columns will be unhooked from the crane by using an
erection tube or shackle with a pull pin which is released from the
ground after the column is stabilized.
The column will be adequately connected and/or braced to safely
support the weight of a ladder with an employee on it.
Inverted Tee Beams
Employees erecting inverted tee beams, at a height of 6 to 40
ft, will erect the beam, make initial connections, and final
alignment from a ladder. If the employee needs to reach over the
side of the beam to bar or make an adjustment to the alignment of
the beam, they will mount the beam and be tied off to the lifting
device in the beam after ensuring the load has been stabilized on
its bearing. To disconnect the crane from the beam an employee will
stand a ladder against the beam. Because the use of ladders is not
practical at heights above 40 ft, beams will be initially placed
with the use of tag lines and their final alignment made by a
person on a manlift or similar employee positioning systems.
Spandrel Beams
Spandrel beams at the exterior of the building will be aligned
as closely as possible with the use of tag lines with the final
placement of the spandrel beam made from a ladder at the open end
of the structure. A ladder will be used to make the initial
connections and a ladder will be used to disconnect the crane. The
other end of the beam will be placed by the designated erector from
the double tee deck under the observation of the safety
monitor.
The beams will be adequately connected and/or braced to safely
support the weight of a ladder with an employee on it.
Floor and Roof Members
During installation of the precast concrete floor and/or roof
members, the work deck continuously increases in area as more and
more units are being erected and positioned. Thus, the unprotected
floor/roof perimeter is constantly modified with the leading edge
changing location as each member is installed. The fall protection
for workers at the leading edge shall be assured by properly
constructed and maintained control zone lines not more than 60 ft
away from the leading edge supplemented by a safety monitoring
system to ensure the safety of all designated erectors working
within the area defined by the control zone lines.
The hollow core slabs erected on the masonry portion of the
building will be erected and grouted using the safety monitoring
system. Grout will be placed in the space between the end of the
slab and face shell of the concrete masonry by dumping from a
wheelbarrow. The grout in the keyways between the slabs will be
dumped from a wheelbarrow and then spread with long handled tools,
allowing the worker to stand erect facing toward the unprotected
edge and back from any work deck edge.
Whenever possible, the designated erectors will approach the
incoming member at the leading edge only after it is below waist
height so that the member itself provides protection against
falls.
Except for the situations described below, when the arriving
floor or roof member is within 2 to 3 inches of its final position,
the designated erectors can then proceed to their position of
erection at each end of the member under the control of the safety
monitor. Crane hooks will be unhooked from double tee members by
designated erectors under the direction and supervision of the
safety monitor.
Designated erectors, while waiting for the next floor or roof
member, will be constantly under the control of the safety monitor
for fall protection and are directed to stay a minimum of six (6)
ft from the edge. In the event a designated erector must move from
one end of a member, which has just been placed at the leading
edge, they must first move away from the leading edge a minimum of
six (6) ft and then progress to the other end while maintaining the
minimum distance of six (6) ft at all times.
Erection of double tees, where conditions require bearing of one
end into a closed pocket and the other end on a beam ledge,
restricting the tee legs from going directly into the pockets,
require special considerations. The tee legs that are to bear in
the closed pocket must hang lower than those at the beam bearing.
The double tee will be “two-lined” in order to elevate one end
higher than the other to allow for the low end to be ducked into
the closed pocket using the following procedure.
The double tee will be rigged with a standard four-way spreader
off of the main load line. An additional choker will be attached to
the married point of the two-legged spreader at the end of the tee
that is to be elevated. The double tee will be hoisted with the
main load line and swung into a position as close as possible to
the tee's final bearing elevation. When the tee is in this position
and stabilized, the whip line load block will be lowered to just
above the tee deck. At this time, two erectors will walk out on the
suspended tee deck at midspan of the tee member and pull the load
block to the end of the tee to be elevated and attach the
additional choker to the load block. The possibility of
entanglement with the crane lines and other obstacles during this
two lining process while raising and lowering the crane block on
that second line could be hazardous to an encumbered employee.
Therefore, the designated erectors will not tie off during any part
of this process. While the designated erectors are on the double
tee, the safety monitoring system will be used. After attaching the
choker, the two erectors then step back on the previously erected
tee deck and signal the crane operator to hoist the load with the
whip line to the elevation that will allow for enough clearance to
let the low end tee legs slide into the pockets when the main load
line is lowered. The erector, who is handling the lowered end of
the tee at the closed pocket bearing, will step out on the
suspended tee. An erection bar will then be placed between the end
of the tee leg and the inside face of the pocketed spandrel member.
The tee is barred away from the pocketed member to reduce the
friction and lateral force against the pocketed member. As the tee
is being lowered, the other erector remains on the tee which was
previously erected to handle the other end. At this point the tee
is slowly lowered by the crane to a point where the tee legs can
freely slide into the pockets. The erector working the lowered end
of the tee must keep pressure on the bar between the tee and the
face of the pocketed spandrel member to very gradually let the tee
legs slide into the pocket to its proper bearing dimension. The tee
is then slowly lowered into its final erected position.
The designated erector should be allowed onto the suspended
double tee, otherwise there is no control over the horizontal
movement of the double tee and this movement could knock the
spandrel off of its bearing or the column out of plumb. The control
necessary to prevent hitting the spandrel can only be done safely
from the top of the double tee being erected.
Loadbearing Wall Panels: The erection of the loadbearing wall
panels on the elevated decks requires the use of a safety monitor
and a controlled access zone that is a minimum of 25 ft and a
maximum of 1/2 the length of the wall panels away from the
unprotected edge, so that designated erectors can move freely and
unencumbered when receiving the panels. Bracing, if required for
stability, will be installed by ladder. After the braces are
secured, the crane will be disconnected from the wall by using a
ladder. The wall to wall connections will also be performed from a
ladder.
Non-Loadbearing Panels (Cladding): The locating of survey lines,
panel layout and other installation prerequisites (prewelding,
etc.) for non-loadbearing panels (cladding) will not commence until
floor perimeter and floor openings have been protected. In some
areas, it is necessary because of panel configuration to remove the
perimeter protection as the cladding is being installed. Removal of
perimeter protection will be performed on a bay to bay basis, just
ahead of cladding erection to minimize temporarily unprotected
floor edges. Those workers within 6 ft of the edge, receiving and
positioning the cladding when the perimeter protection is removed
shall be tied off.
Detailing
Employees exposed to falls of six (6) feet or more to lower
levels, who are not actively engaged in leading edge work or
connecting activity, such as welding, bolting, cutting, bracing,
guying, patching, painting or other operations, and who are working
less than six (6) ft from an unprotected edge will be tied off at
all times or guardrails will be installed. Employees engaged in
these activities but who are more than six (6) ft from an
unprotected edge as defined by the control zone lines, do not
require fall protection but a warning line or control lines must be
erected to remind employees they are approaching an area where fall
protection is required.
IV. Conventional Fall Protection Considered for the Point of
Erection or Leading Edge Erection Operations A. Personal Fall
Arrest Systems
In this particular erection sequence and procedure, personal
fall arrest systems requiring body belt/harness systems, lifelines
and lanyards will not reduce possible hazards to workers and will
create offsetting hazards during their usage at the leading edge of
precast/prestressed concrete construction.
Leading edge erection and initial connections are conducted by
employees who are specifically trained to do this type of work and
are trained to recognize the fall hazards. The nature of such work
normally exposes the employee to the fall hazard for a short period
of time and installation of fall protection systems for a short
duration is not feasible because it exposes the installers of the
system to the same fall hazard, but for a longer period of
time.
1. It is necessary that the employee be able to move freely
without encumbrance in order to guide the sections of precast
concrete into their final position without having lifelines
attached which will restrict the employee's ability to move about
at the point of erection.
2. A typical procedure requires 2 or more workers to maneuver
around each other as a concrete member is positioned to fit into
the structure. If they are each attached to a lifeline, part of
their attention must be diverted from their main task of
positioning a member weighing several tons to the task of avoiding
entanglements of their lifelines or avoiding tripping over
lanyards. Therefore, if these workers are attached to lanyards,
more fall potential would result than from not using such a
device.
In this specific erection sequence and procedure, retractable
lifelines do not solve the problem of two workers becoming tangled.
In fact, such a tangle could prevent the lifeline from retracting
as the worker moved, thus potentially exposing the worker to a fall
greater than 6 ft. Also, a worker crossing over the lifeline of
another worker can create a hazard because the movement of one
person can unbalance the other. In the event of a fall by one
person there is a likelihood that the other person will be caused
to fall as well. In addition, if contamination such as grout
(during hollow core grouting) enters the retractable housing it can
cause excessive wear and damage to the device and could clog the
retracting mechanism as the lanyard is dragged across the deck.
Obstructing the cable orifice can defeat the device's shock
absorbing function, produce cable slack and damage, and adversely
affect cable extraction and retraction.
3. Employees tied to a lifeline can be trapped and crushed by
moving structural members if the employee becomes restrained by the
lanyard or retractable lifeline and cannot get out of the path of
the moving load.
The sudden movement of a precast concrete member being raised by
a crane can be caused by a number of factors. When this happens, a
connector may immediately have to move a considerable distance to
avoid injury. If a tied off body belt/harness is being used, the
connector could be trapped. Therefore, there is a greater risk of
injury if the connector is tied to the structure for this specific
erection sequence and procedure.
When necessary to move away from a retractable device, the
worker cannot move at a rate greater than the device locking speed
typically 3.5 to 4.5 ft/sec. When moving toward the device it is
necessary to move at a rate which does not permit cable slack to
build up. This slack may cause cable retraction acceleration and
cause a worker to lose their balance by applying a higher than
normal jerking force on the body when the cable suddenly becomes
taut after building up momentum. This slack can also cause damage
to the internal spring-loaded drum, uneven coiling of cable on the
drum, and possible cable damage.
The factors causing sudden movements for this location
include:
(a) Cranes
(1) Operator error.
(2) Site conditions (soft or unstable ground).
(3) Mechanical failure.
(4) Structural failure.
(5) Rigging failure.
(6) Crane signal/radio communication failure.
(b) Weather Conditions
(1) Wind (strong wind/sudden gusting) - particularly a problem
with the large surface areas of precast concrete members.
(2) Snow/rain (visibility).
(3) Fog (visibility).
(4) Cold - causing slowed reactions or mechanical problems.
(c) Structure/Product Conditions.
(1) Lifting Eye failure.
(2) Bearing failure or slippage.
(3) Structure shifting.
(4) Bracing failure.
(5) Product failure.
(d) Human Error.
(1) Incorrect tag line procedure.
(2) Tag line hang-up.
(3) Incorrect or misunderstood crane signals.
(4) Misjudged elevation of member.
(5) Misjudged speed of member.
(6) Misjudged angle of member.
4. Anchorages or special attachment points could be cast into
the precast concrete members if sufficient preplanning and
consideration of erectors' position is done before the members are
cast. Any hole or other attachment must be approved by the engineer
who designed the member. It is possible that some design
restrictions will not allow a member to be weakened by an
additional hole; however, it is anticipated that such situations
would be the exception, not the rule. Attachment points, other than
on the deck surface, will require removal and/or patching. In order
to remove and/or patch these points, requires the employee to be
exposed to an additional fall hazard at an unprotected perimeter.
The fact that attachment points could be available anywhere on the
structure does not eliminate the hazards of using these points for
tying off as discussed above. A logical point for tying off on
double tees would be using the lifting loops, except that they must
be cut off to eliminate a tripping hazard at an appropriate
time.
5. Providing attachment at a point above the walking/working
surface would also create fall exposures for employees installing
their devices. Final positioning of a precast concrete member
requires it to be moved in such a way that it must pass through the
area that would be occupied by the lifeline and the lanyards
attached to the point above. Resulting entanglements of lifelines
and lanyards on a moving member could pull employees from the work
surface. Also, the structure is being created and, in most cases,
there is no structure above the members being placed.
(a) Temporary structural supports, installed to provide
attaching points for lifelines limit the space which is essential
for orderly positioning, alignment and placement of the precast
concrete members. To keep the lanyards a reasonable and manageable
length, lifeline supports would necessarily need to be in proximity
to the positioning process. A sudden shift of the precast concrete
member being positioned because of wind pressure or crane movement
could make it strike the temporary supporting structure, moving it
suddenly and causing tied off employees to fall.
(b) The time in manhours which would be expended in placing and
maintaining temporary structural supports for lifeline attaching
points could exceed the expended manhours involved in placing the
precast concrete members. No protection could be provided for the
employees erecting the temporary structural supports and these
supports would have to be moved for each successive step in the
construction process, thus greatly increasing the employee's
exposure to the fall hazard.
(c) The use of a cable strung horizontally between two columns
to provide tie off lines for erecting or walking a beam for
connecting work is not feasible and creates a greater hazard on
this multi-story building for the following reasons:
(1) If a connector is to use such a line, it must be installed
between the two columns. To perform this installation requires an
erector to have more fall exposure time attaching the cable to the
columns than would be spent to make the beam to column connection
itself.
(2) If such a line is to be installed so that an erector can
walk along a beam, it must be overhead or below him. For example,
if a connector must walk along a 24 in. wide beam, the presence of
a line next to the connector at waist level, attached directly to
the columns, would prevent the connector from centering their
weight over the beam and balancing themselves. Installing the line
above the connector might be possible on the first level of a
two-story column; however, the column may extend only a few feet
above the floor level at the second level or be flush with the
floor level. Attaching the line to the side of the beam could be a
solution; however, it would require the connector to attach the
lanyard below foot level which would most likely extend a fall
farther than 6 ft.
(3) When lines are strung over every beam, it becomes more and
more difficult for the crane operator to lower a precast concrete
member into position without the member becoming fouled. Should the
member become entangled, it could easily dislodge the line from a
column. If a worker is tied to it at the time, a fall could be
caused.
6. The ANSI A10.14-1991 American National Standard for
Construction and Demolition Operations - Requirements for Safety
Belts, Harnesses, Lanyards and Lifelines for Construction and
Demolition Use, states that the anchor point of a lanyard or
deceleration device should, if possible, be located above the
wearer's belt or harness attachment. ANSI A10.14 also states that a
suitable anchorage point is one which is located as high as
possible to prevent contact with an obstruction below should the
worker fall. Most manufacturers also warn in the user's handbook
that the safety block/retractable lifeline must be positioned above
the D-ring (above the work space of the intended user) and OSHA
recommends that fall arrest and restraint equipment be used in
accordance with the manufacturer's instructions.
Attachment of a retractable device to a horizontal cable near
floor level or using the inserts in the floor or roof members may
result in increased free fall due to the dorsal D-ring of the
full-body harness riding higher than the attachment point of the
snaphook to the cable or insert (e.g., 6 foot tall worker with a
dorsal D-ring at 5 feet above the floor or surface, reduces the
working length to only one foot, by placing the anchorage five feet
away from the fall hazard). In addition, impact loads may exceed
maximum fall arrest forces (MAF) because the fall arrest D-ring
would be 4 to 5 feet higher than the safety block/retractable
lifeline anchored to the walking-working surface; and the potential
for swing hazards is increased.
Manufacturers also require that workers not work at a level
where the point of snaphook attachment to the body harness is above
the device because this will increase the free fall distance and
the deceleration distance and will cause higher forces on the body
in the event of an accidental fall.
Manufacturers recommend an anchorage for the retractable
lifeline which is immovably fixed in space and is independent of
the user's support systems. A moveable anchorage is one which can
be moved around (such as equipment or wheeled vehicles) or which
can deflect substantially under shock loading (such as a horizontal
cable or very flexible beam). In the case of a very flexible
anchorage, a shock load applied to the anchorage during fall arrest
can cause oscillation of the flexible anchorage such that the
retractable brake mechanism may undergo one or more cycles of
locking/unlocking/locking (ratchet effect) until the anchorage
deflection is dampened. Therefore, use of a moveable anchorage
involves critical engineering and safety factors and should only be
considered after fixed anchorage has been determined to be not
feasible.
Horizontal cables used as an anchorage present an additional
hazard due to amplification of the horizontal component of maximum
arrest force (of a fall) transmitted to the points where the
horizontal cable is attached to the structure. This amplification
is due to the angle of sag of a horizontal cable and is most severe
for small angles of sag. For a cable sag angle of 2 degrees the
horizontal force on the points of cable attachment can be amplified
by a factor of 15.
It is also necessary to install the retractable device
vertically overhead to minimize swing falls. If an object is in the
worker's swing path (or that of the cable) hazardous situations
exist: (1) due to the swing, horizontal speed of the user may be
high enough to cause injury when an obstacle in the swing fall path
is struck by either the user or the cable; (2) the total vertical
fall distance of the user may be much greater than if the user had
fallen only vertically without a swing fall path.
With retractable lines, overconfidence may cause the worker to
engage in inappropriate behavior, such as approaching the perimeter
of a floor or roof at a distance appreciably greater than the
shortest distance between the anchorage point and the leading edge.
Though the retractable lifeline may arrest a worker's fall before
he or she has fallen a few feet, the lifeline may drag along the
edge of the floor or beam and swing the worker like a pendulum
until the line has moved to a position where the distance between
the anchorage point and floor edge is the shortest distance between
those two points. Accompanying this pendulum swing is a lowering of
the worker, with the attendant danger that he or she may violently
impact the floor or some obstruction below.
The risk of a cable breaking is increased if a lifeline is
dragged sideways across the rough surface or edge of a concrete
member at the same moment that the lifeline is being subjected to a
maximum impact loading during a fall. The typical 3/16 in. cable in
a retractable lifeline has a breaking strength of from 3000 to 3700
lbs.
7. The competent person, who can take into account the
specialized operations being performed on this project, should
determine when and where a designated erector cannot use a personal
fall arrest system.
B. Safety Net Systems
The nature of this particular precast concrete erection worksite
precludes the safe use of safety nets where point of erection or
leading edge work must take place.
1. To install safety nets in the interior high bay of the single
story portion of the building poses rigging attachment problems.
Structural members do not exist to which supporting devices for
nets can be attached in the area where protection is required. As
the erection operation advances, the location of point of erection
or leading edge work changes constantly as each member is attached
to the structure. Due to this constant change it is not feasible to
set net sections and build separate structures to support the
nets.
2. The nature of the erection process for the precast concrete
members is such that an installed net would protect workers as they
position and secure only one structural member. After each member
is stabilized the net would have to be moved to a new location
(this could mean a move of 8 to 10 ft or the possibility of a move
to a different level or area of the structure) to protect workers
placing the next piece in the construction sequence. The result
would be the installation and dismantling of safety nets repeatedly
throughout the normal work day. As the time necessary to install a
net, test, and remove it is significantly greater than the time
necessary to position and secure a precast concrete member, the
exposure time for the worker installing the safety net would be far
longer than for the workers whom the net is intended to protect.
The time exposure repeats itself each time the nets and supporting
hardware must be moved laterally or upward to provide protection at
the point of erection or leading edge.
3. Strict interpretation of § 1926.502(c) requires that
operations shall not be undertaken until the net is in place and
has been tested. With the point of erection constantly changing,
the time necessary to install and test a safety net significantly
exceeds the time necessary to position and secure the concrete
member.
4. Use of safety nets on exposed perimeter wall openings and
opensided floors, causes attachment points to be left in
architectural concrete which must be patched and filled with
matching material after the net supporting hardware is removed. In
order to patch these openings, additional numbers of employees must
be suspended by swing stages, boatswain chairs or other devices,
thereby increasing the amount of fall exposure time to
employees.
5. Installed safety nets pose an additional hazard at the
perimeter of the erected structure where limited space is available
in which members can be turned after being lifted from the ground
by the crane. There would be a high probability that the member
being lifted could become entangled in net hardware, cables,
etc.
6. The use of safety nets where structural wall panels are being
erected would prevent movement of panels to point of installation.
To be effective, nets would necessarily have to provide protection
across the area where structural supporting wall panels would be
set and plumbed before roof units could be placed.
7. Use of a tower crane for the erection of the high rise
portion of the structure poses a particular hazard in that the
crane operator cannot see or judge the proximity of the load in
relation to the structure or nets. If the signaler is looking
through nets and supporting structural devices while giving
instructions to the crane operator, it is not possible to judge
precise relationships between the load and the structure itself or
to nets and supporting structural devices. This could cause the
load to become entangled in the net or hit the structure causing
potential damage.
C. Guardrail Systems
On this particular worksite, guardrails, barricades, ropes,
cables or other perimeter guarding devices or methods on the
erection floor will pose problems to safe erection procedures.
Typically, a floor or roof is erected by placing 4 to 10 ft wide
structural members next to one another and welding or grouting them
together. The perimeter of a floor and roof changes each time a new
member is placed into position. It is unreasonable and virtually
impossible to erect guardrails and toe boards at the ever changing
leading edge of a floor or roof.
1. To position a member safely it is necessary to remove all
obstructions extending above the floor level near the point of
erection. Such a procedure allows workers to swing a new member
across the erected surface as necessary to position it properly
without worrying about knocking material off of this surface.
Hollow core slab erection on the masonry wall requires
installation of the perimeter protection where the masonry wall has
to be constructed. This means the guardrail is installed then
subsequently removed to continue the masonry construction. The
erector will be exposed to a fall hazard for a longer period of
time while installing and removing perimeter protection than while
erecting the slabs.
In hollow core work, as in other precast concrete erection,
others are not typically on the work deck until the precast
concrete erection is complete. The deck is not complete until the
leveling, aligning, and grouting of the joints is done. It is
normal practice to keep others off the deck until at least the next
day after the installation is complete to allow the grout to
harden.
2. There is no permanent boundary until all structural members
have been placed in the floor or roof. At the leading edge, workers
are operating at the temporary edge of the structure as they work
to position the next member in the sequence. Compliance with the
standard would require a guardrail and toe board be installed along
this edge. However, the presence of such a device would prevent a
new member from being swung over the erected surface low enough to
allow workers to control it safely during the positioning process.
Further, these employees would have to work through the guardrail
to align the new member and connect it to the structure. The
guardrail would not protect an employee who must lean through it to
do the necessary work, rather it would hinder the employee to such
a degree that a greater hazard is created than if the guardrail
were absent.
3. Guardrail requirements pose a hazard at the leading edge of
installed floor or roof sections by creating the possibility of
employees being caught between guardrails and suspended loads. The
lack of a clear work area in which to guide the suspended load into
position for placement and welding of members into the existing
structure creates still further hazards.
4. Where erection processes require precast concrete stairways
or openings to be installed as an integral part of the overall
erection process, it must also be recognized that guardrails or
handrails must not project above the surface of the erection floor.
Such guardrails should be terminated at the level of the erection
floor to avoid placing hazardous obstacles in the path of a member
being positioned.
V. Other Fall Protection Measures Considered for This Job
The following is a list and explanation of other fall protection
measures available and an explanation of limitations for use on
this particular jobsite. If during the course of erecting the
building the employee sees an area that could be erected more
safely by the use of these fall protection measures, the foreman
should be notified.
A. Scaffolds are not used because:
1. The leading edge of the building is constantly changing and
the scaffolding would have to be moved at very frequent intervals.
Employees erecting and dismantling the scaffolding would be exposed
to fall hazards for a greater length of time than they would by
merely erecting the precast concrete member.
2. A scaffold tower could interfere with the safe swinging of a
load by the crane.
3. Power lines, terrain and site do not allow for the safe use
of scaffolding.
B. Vehicle mounted platforms are not used because:
1. A vehicle mounted platform will not reach areas on the deck
that are erected over other levels.
2. The leading edge of the building is usually over a lower
level of the building and this lower level will not support the
weight of a vehicle mounted platform.
3. A vehicle mounted platform could interfere with the safe
swinging of a load by the crane, either by the crane swinging the
load over or into the equipment.
4. Power lines and surrounding site work do not allow for the
safe use of a vehicle mounted platform.
C. Crane suspended personnel platforms are not used because:
1. A second crane close enough to suspend any employee in the
working and erecting area could interfere with the safe swinging of
a load by the crane hoisting the product to be erected.
2. Power lines and surrounding site work do not allow for the
safe use of a second crane on the job.
VI. Enforcement
Constant awareness of and respect for fall hazards, and
compliance with all safety rules are considered conditions of
employment. The jobsite Superintendent, as well as individuals in
the Safety and Personnel Department, reserve the right to issue
disciplinary warnings to employees, up to and including
termination, for failure to follow the guidelines of this
program.
VII. Accident Investigations
All accidents that result in injury to workers, regardless of
their nature, shall be investigated and reported. It is an integral
part of any safety program that documentation take place as soon as
possible so that the cause and means of prevention can be
identified to prevent a reoccurrence.
In the event that an employee falls or there is some other
related, serious incident occurring, this plan shall be reviewed to
determine if additional practices, procedures, or training need to
be implemented to prevent similar types of falls or incidents from
occurring.
VIII. Changes to Plan
Any changes to the plan will be approved by (name of the
qualified person). This plan shall be reviewed by a qualified
person as the job progresses to determine if additional practices,
procedures or training needs to be implemented by the competent
person to improve or provide additional fall protection. Workers
shall be notified and trained, if necessary, in the new procedures.
A copy of this plan and all approved changes shall be maintained at
the jobsite.
Sample Fall Protection Plan for Residential Construction (Insert
Company Name)
This Fall Protection Plan Is Specific For The Following
Project:
Location of Job Date Plan Prepared or Modified Plan Prepared By
Plan Approved By Plan Supervised By
The following Fall Protection Plan is a sample program prepared
for the prevention of injuries associated with falls. A Fall
Protection Plan must be developed and evaluated on a site by site
basis. It is recommended that builders discuss the written Fall
Protection Plan with their OSHA Area Office prior to going on a
jobsite.
I. Statement of Company Policy
(Your company name here) is dedicated to the protection of its
employees from on-the-job injuries. All employees of (Your company
name here) have the responsibility to work safely on the job. The
purpose of the plan is to supplement our existing safety and health
program and to ensure that every employee who works for (Your
company name here) recognizes workplace fall hazards and takes the
appropriate measures to address those hazards.
This Fall Protection Plan addresses the use of conventional fall
protection at a number of areas on the project, as well as
identifies specific activities that require non-conventional means
of fall protection. During the construction of residential
buildings under 48 feet in height, it is sometimes infeasible or it
creates a greater hazard to use conventional fall protection
systems at specific areas or for specific tasks. The areas or tasks
may include, but are not limited to:
a. Setting and bracing of roof trusses and rafters;
b. Installation of floor sheathing and joists;
c. Roof sheathing operations; and
d. Erecting exterior walls.
In these cases, conventional fall protection systems may not be
the safest choice for builders. This plan is designed to enable
employers and employees to recognize the fall hazards associated
with this job and to establish the safest procedures that are to be
followed in order to prevent falls to lower levels or through holes
and openings in walking/working surfaces.
Each employee will be trained in these procedures and will
strictly adhere to them except when doing so would expose the
employee to a greater hazard. If, in the employee's opinion, this
is the case, the employee is to notify the competent person of
their concern and have the concern addressed before proceeding.
It is the responsibility of (name of competent person) to
implement this Fall Protection Plan. Continual observational safety
checks of work operations and the enforcement of the safety policy
and procedures shall be regularly enforced. The crew supervisor or
foreman (insert name) is responsible for correcting any unsafe
practices or conditions immediately.
It is the responsibility of the employer to ensure that all
employees understand and adhere to the procedures of this plan and
to follow the instructions of the crew supervisor. It is also the
responsibility of the employee to bring to management's attention
any unsafe or hazardous conditions or practices that may cause
injury to either themselves or any other employees. Any changes to
the Fall Protection Plan must be approved by (name of qualified
person).
II. Fall Protection Systems To Be Used on This Job
Installation of roof trusses/rafters, exterior wall erection,
roof sheathing, floor sheathing and joist/truss activities will be
conducted by employees who are specifically trained to do this type
of work and are trained to recognize the fall hazards. The nature
of such work normally exposes the employee to the fall hazard for a
short period of time. This Plan details how (Your company name
here) will minimize these hazards.
Controlled Access Zones
When using the Plan to implement the fall protection options
available, workers must be protected through limited access to high
hazard locations. Before any non-conventional fall protection
systems are used as part of the work plan, a controlled access zone
(CAZ) shall be clearly defined by the competent person as an area
where a recognized hazard exists. The demarcation of the CAZ shall
be communicated by the competent person in a recognized manner,
either through signs, wires, tapes, ropes or chains.
(Your company name here) shall take the following steps to
ensure that the CAZ is clearly marked or controlled by the
competent person:
• All access to the CAZ must be restricted to authorized
entrants;
• All workers who are permitted in the CAZ shall be listed in
the appropriate sections of the Plan (or be visibly identifiable by
the competent person) prior to implementation;
• The competent person shall ensure that all protective elements
of the CAZ be implemented prior to the beginning of work.
Installation Procedures for Roof Truss and Rafter Erection
During the erection and bracing of roof trusses/rafters,
conventional fall protection may present a greater hazard to
workers. On this job, safety nets, guardrails and personal fall
arrest systems will not provide adequate fall protection because
the nets will cause the walls to collapse, while there are no
suitable attachment or anchorage points for guardrails or personal
fall arrest systems.
On this job, requiring workers to use a ladder for the entire
installation process will cause a greater hazard because the worker
must stand on the ladder with his back or side to the front of the
ladder. While erecting the truss or rafter the worker will need
both hands to maneuver the truss and therefore cannot hold onto the
ladder. In addition, ladders cannot be adequately protected from
movement while trusses are being maneuvered into place. Many
workers may experience additional fatigue because of the increase
in overhead work with heavy materials, which can also lead to a
greater hazard.
Exterior scaffolds cannot be utilized on this job because the
ground, after recent backfilling, cannot support the scaffolding.
In most cases, the erection and dismantling of the scaffold would
expose workers to a greater fall hazard than erection of the
trusses/rafters.
On all walls eight feet or less, workers will install interior
scaffolds along the interior wall below the location where the
trusses/rafters will be erected. “Sawhorse” scaffolds constructed
of 46 inch sawhorses and 2 × 10 planks will often allow workers to
be elevated high enough to allow for the erection of trusses and
rafters without working on the top plate of the wall.
In structures that have walls higher than eight feet and where
the use of scaffolds and ladders would create a greater hazard,
safe working procedures will be utilized when working on the top
plate and will be monitored by the crew supervisor. During all
stages of truss/rafter erection the stability of the
trusses/rafters will be ensured at all times.
(Your company name here) shall take the following steps to
protect workers who are exposed to fall hazards while working from
the top plate installing trusses/rafters:
• Only the following trained workers will be allowed to work on
the top plate during roof truss or rafter installation:
• Workers shall have no other duties to perform during
truss/rafter erection procedures;
• All trusses/rafters will be adequately braced before any
worker can use the truss/rafter as a support;
• Workers will remain on the top plate using the previously
stabilized truss/rafter as a support while other trusses/rafters
are being erected;
• Workers will leave the area of the secured trusses only when
it is necessary to secure another truss/rafter;
• The first two trusses/rafters will be set from ladders leaning
on side walls at points where the walls can support the weight of
the ladder; and
• A worker will climb onto the interior top plate via a ladder
to secure the peaks of the first two trusses/rafters being set.
The workers responsible for detaching trusses from cranes and/or
securing trusses at the peaks traditionally are positioned at the
peak of the trusses/rafters. There are also situations where
workers securing rafters to ridge beams will be positioned on top
of the ridge beam.
(Your company name here) shall take the following steps to
protect workers who are exposed to fall hazards while securing
trusses/rafters at the peak of the trusses/ridge beam:
• Only the following trained workers will be allowed to work at
the peak during roof truss or rafter installation:
• Once truss or rafter installation begins, workers not involved
in that activity shall not stand or walk below or adjacent to the
roof opening or exterior walls in any area where they could be
struck by falling objects;
• Workers shall have no other duties than securing/bracing the
trusses/ridge beam;
• Workers positioned at the peaks or in the webs of trusses or
on top of the ridge beam shall work from a stable position, either
by sitting on a “ridge seat” or other equivalent surface that
provides additional stability or by positioning themselves in
previously stabilized trusses/rafters and leaning into and reaching
through the trusses/rafters;
• Workers shall not remain on or in the peak/ridge any longer
than necessary to safely complete the task.
Roof Sheathing Operations
Workers typically install roof sheathing after all
trusses/rafters and any permanent truss bracing is in place. Roof
structures are unstable until some sheathing is installed, so
workers installing roof sheathing cannot be protected from fall
hazards by conventional fall protection systems until it is
determined that the roofing system can be used as an anchorage
point. At that point, employees shall be protected by a personal
fall arrest system.
Trusses/rafters are subject to collapse if a worker falls while
attached to a single truss with a belt/harness. Nets could also
cause collapse, and there is no place to attach guardrails.
All workers will ensure that they have secure footing before
they attempt to walk on the sheathing, including cleaning
shoes/boots of mud or other slip hazards.
To minimize the time workers must be exposed to a fall hazard,
materials will be staged to allow for the quickest installation of
sheathing.
(Your company name here) shall take the following steps to
protect workers who are exposed to fall hazards while installing
roof sheathing:
• Once roof sheathing installation begins, workers not involved
in that activity shall not stand or walk below or adjacent to the
roof opening or exterior walls in any area where they could be
struck by falling objects;
• The competent person shall determine the limits of this area,
which shall be clearly communicated to workers prior to placement
of the first piece of roof sheathing;
• The competent person may order work on the roof to be
suspended for brief periods as necessary to allow other workers to
pass through such areas when this would not create a greater
hazard;
• Only qualified workers shall install roof sheathing;
• The bottom row of roof sheathing may be installed by workers
standing in truss webs;
• After the bottom row of roof sheathing is installed, a slide
guard extending the width of the roof shall be securely attached to
the roof. Slide guards are to be constructed of no less than
nominal 4” height capable of limiting the uncontrolled slide of
workers. Workers should install the slide guard while standing in
truss webs and leaning over the sheathing;
• Additional rows of roof sheathing may be installed by workers
positioned on previously installed rows of sheathing. A slide guard
can be used to assist workers in retaining their footing during
successive sheathing operations; and
• Additional slide guards shall be securely attached to the roof
at intervals not to exceed 13 feet as successive rows of sheathing
are installed. For roofs with pitches in excess of 9-in-12, slide
guards will be installed at four-foot intervals.
• When wet weather (rain, snow, or sleet) are present, roof
sheathing operations shall be suspended unless safe footing can be
assured for those workers installing sheathing.
• When strong winds (above 40 miles per hour) are present, roof
sheathing operations are to be suspended unless wind breakers are
erected.
Installation of Floor Joists and Sheathing
During the installation of floor sheathing/joists (leading edge
construction), the following steps shall be taken to protect
workers:
• Only the following trained workers will be allowed to install
floor joists or sheathing:
• Materials for the operations shall be conveniently staged to
allow for easy access to workers;
• The first floor joists or trusses will be rolled into position
and secured either from the ground, ladders or sawhorse
scaffolds;
• Each successive floor joist or truss will be rolled into place
and secured from a platform created from a sheet of plywood laid
over the previously secured floor joists or trusses;
• Except for the first row of sheathing which will be installed
from ladders or the ground, workers shall work from the established
deck; and
• Any workers not assisting in the leading edge construction
while leading edges still exist (e.g. cutting the decking for the
installers) shall not be permitted within six feet of the leading
edge under construction.
Erection of Exterior Walls
During the construction and erection of exterior walls,
employers shall take the following steps to protect workers:
• Only the following trained workers will be allowed to erect
exterior walls:
• A painted line six feet from the perimeter will be clearly
marked prior to any wall erection activities to warn of the
approaching unprotected edge;
• Materials for operations shall be conveniently staged to
minimize fall hazards; and
• Workers constructing exterior walls shall complete as much
cutting of materials and other preparation as possible away from
the edge of the deck.
III. Enforcement
Constant awareness of and respect for fall hazards, and
compliance with all safety rules are considered conditions of
employment. The crew supervisor or foreman, as well as individuals
in the Safety and Personnel Department, reserve the right to issue
disciplinary warnings to employees, up to and including
termination, for failure to follow the guidelines of this
program.
IV. Accident Investigations
All accidents that result in injury to workers, regardless of
their nature, shall be investigated and reported. It is an integral
part of any safety program that documentation take place as soon as
possible so that the cause and means of prevention can be
identified to prevent a reoccurrence.
In the event that an employee falls or there is some other
related, serious incident occurring, this plan shall be reviewed to
determine if additional practices, procedures, or training need to
be implemented to prevent similar types of falls or incidents from
occurring.
V. Changes to Plan
Any changes to the plan will be approved by (name of the
qualified person). This plan shall be reviewed by a qualified
person as the job progresses to determine if additional practices,
procedures or training needs to be implemented by the competent
person to improve or provide additional fall protection. Workers
shall be notified and trained, if necessary, in the new procedures.
A copy of this plan and all approved changes shall be maintained at
the jobsite.
[59 FR 40730, Aug. 9, 1994]
Appendix E to Subpart V of Part 1926 - Protection From Flames and Electric Arcs
29:8.1.1.1.1.22.19.20.31 : Appendix E
Appendix E to Subpart V of Part 1926 - Protection From Flames and
Electric Arcs I. Introduction
Paragraph (g) of § 1926.960 addresses protecting employees from
flames and electric arcs. This paragraph requires employers to: (1)
Assess the workplace for flame and electric-arc hazards (paragraph
(g)(1)); (2) estimate the available heat energy from electric arcs
to which employees would be exposed (paragraph (g)(2)); (3) ensure
that employees wear clothing that will not melt, or ignite and
continue to burn, when exposed to flames or the estimated heat
energy (paragraph (g)(3)); and (4) ensure that employees wear
flame-resistant clothing 1 and protective clothing and other
protective equipment that has an arc rating greater than or equal
to the available heat energy under certain conditions (paragraphs
(g)(4) and (g)(5)). This appendix contains information to help
employers estimate available heat energy as required by §
1926.960(g)(2), select protective clothing and other protective
equipment with an arc rating suitable for the available heat energy
as required by § 1926.960(g)(5), and ensure that employees do not
wear flammable clothing that could lead to burn injury as addressed
by §§ 1926.960(g)(3) and (g)(4).
1 Flame-resistant clothing includes clothing that is inherently
flame resistant and clothing chemically treated with a flame
retardant. (See ASTM F1506-10a, Standard Performance
Specification for Flame Resistant Textile Materials for Wearing
Apparel for Use by Electrical Workers Exposed to Momentary Electric
Arc and Related Thermal Hazards, and ASTM F1891-12 Standard
Specification for Arc and Flame Resistant Rainwear.)
II. Assessing the Workplace for Flame and Electric-Arc Hazards
Paragraph (g)(1) of § 1926.960 requires the employer to assess
the workplace to identify employees exposed to hazards from flames
or from electric arcs. This provision ensures that the employer
evaluates employee exposure to flames and electric arcs so that
employees who face such exposures receive the required protection.
The employer must conduct an assessment for each employee who
performs work on or near exposed, energized parts of electric
circuits.
A. Assessment Guidelines
Sources electric arcs. Consider possible sources of
electric arcs, including:
• Energized circuit parts not guarded or insulated,
• Switching devices that produce electric arcs in normal
operation,
• Sliding parts that could fault during operation (for example,
rack-mounted circuit breakers), and
• Energized electric equipment that could fail (for example,
electric equipment with damaged insulation or with evidence of
arcing or overheating).
Exposure to flames. Identify employees exposed to hazards
from flames. Factors to consider include:
• The proximity of employees to open flames, and
• For flammable material in the work area, whether there is a
reasonable likelihood that an electric arc or an open flame can
ignite the material.
Probability that an electric arc will occur. Identify
employees exposed to electric-arc hazards. The Occupational Safety
and Health Administration will consider an employee exposed to
electric-arc hazards if there is a reasonable likelihood that an
electric arc will occur in the employee's work area, in other
words, if the probability of such an event is higher than it is for
the normal operation of enclosed equipment. Factors to consider
include:
• For energized circuit parts not guarded or insulated, whether
conductive objects can come too close to or fall onto the energized
parts,
• For exposed, energized circuit parts, whether the employee is
closer to the part than the minimum approach distance established
by the employer (as permitted by § 1926.960(c)(1)(iii)).
• Whether the operation of electric equipment with sliding parts
that could fault during operation is part of the normal operation
of the equipment or occurs during servicing or maintenance, and
• For energized electric equipment, whether there is evidence of
impending failure, such as evidence of arcing or overheating.
B. Examples
Table 1 provides task-based examples of exposure
assessments.
Table 1 - Example Assessments for Various
Tasks
|
Task |
Is employee exposed to flame
or electric-arc hazard? |
| Normal operation
of enclosed equipment, such as closing or opening a switch |
The employer properly installs
and maintains enclosed equipment, and there is no evidence of
impending failure |
No. |
|
There is evidence of arcing or
overheating |
Yes. |
|
Parts of the equipment are
loose or sticking, or the equipment otherwise exhibits signs of
lack of maintenance |
Yes. |
|
Servicing electric equipment, such as racking in a circuit breaker
or replacing a switch |
Yes. |
| Inspection of
electric equipment with exposed energized parts |
The employee is not holding
conductive objects and remains outside the minimum approach
distance established by the employer |
No. |
|
The employee is holding a
conductive object, such as a flashlight, that could fall or
otherwise contact energized parts (irrespective of whether the
employee maintains the minimum approach distance) |
Yes. |
|
The employee is closer than
the minimum approach distance established by the employer (for
example, when wearing rubber insulating gloves or rubber insulating
gloves and sleeves) |
Yes. |
| Using
open flames, for example, in wiping cable splice sleeves |
Yes. |
III. Protection Against Burn Injury A. Estimating Available Heat
Energy
Calculation methods. Paragraph (g)(2) of § 1926.960
provides that, for each employee exposed to an electric-arc hazard,
the employer must make a reasonable estimate of the heat energy to
which the employee would be exposed if an arc occurs. Table 2 lists
various methods of calculating values of available heat energy from
an electric circuit. The Occupational Safety and Health
Administration does not endorse any of these specific methods. Each
method requires the input of various parameters, such as fault
current, the expected length of the electric arc, the distance from
the arc to the employee, and the clearing time for the fault (that
is, the time the circuit protective devices take to open the
circuit and clear the fault). The employer can precisely determine
some of these parameters, such as the fault current and the
clearing time, for a given system. The employer will need to
estimate other parameters, such as the length of the arc and the
distance between the arc and the employee, because such parameters
vary widely.
Table 2 - Methods of Calculating Incident
Heat Energy From an Electric Arc
| 1. Standard for
Electrical Safety Requirements for Employee Workplaces, NFPA
70E-2012, Annex D, “Sample Calculation of Flash Protection
Boundary.” |
| 2. Doughty, T.E.,
Neal, T.E., and Floyd II, H.L., “Predicting Incident Energy to
Better Manage the Electric Arc Hazard on 600 V Power Distribution
Systems,” Record of Conference Papers IEEE IAS 45th Annual
Petroleum and Chemical Industry Conference, September 28 - 30,
1998. |
| 3. Guide for
Performing Arc-Flash Hazard Calculations, IEEE Std 1584-2002,
1584a--2004 (Amendment 1 to IEEE Std 1584-2002), and 1584b-2011
(Amendment 2: Changes to Clause 4 of IEEE Std 1584-2002). * |
| 4. ARCPRO, a
commercially available software program developed by Kinectrics,
Toronto, ON, CA. |
| * This appendix
refers to IEEE Std 1584-2002 with both amendments as IEEE Std
1584b-2011. |
The amount of heat energy calculated by any of the methods is
approximatelyinversely proportional to the square of the distance
between the employee and the arc. In other words, if the employee
is very close to the arc, the heat energy is very high; but if the
employee is just a few more centimeters away, the heat energy drops
substantially. Thus, estimating the distance from the arc to the
employee is key to protecting employees.
The employer must select a method of estimating incident heat
energy that provides a reasonable estimate of incident heat energy
for the exposure involved. Table 3 shows which methods provide
reasonable estimates for various exposures.
Table 3 - Selecting a Reasonable
Incident-Energy Calculation Method 1
| Incident-energy
calculation method |
600 V and Less
2 |
601 V to 15 kV
2 |
More than 15
kV |
| 1Φ |
3Φa |
3Φb |
1Φ |
3Φa |
3Φb |
1Φ |
3Φa |
3Φb |
| NFPA 70E-2012
Annex D (Lee equation) |
Y-C |
Y |
N |
Y-C |
Y-C |
N |
N 3 |
N 3 |
N 3 |
| Doughty, Neal, and
Floyd |
Y-C |
Y |
Y |
N |
N |
N |
N |
N |
N |
| IEEE Std
1584b-2011 |
Y |
Y |
Y |
Y |
Y |
Y |
N |
N |
N |
| ARCPRO |
Y |
N |
N |
Y |
N |
N |
Y |
Y 4 |
Y 4 |
Selecting a reasonable distance from the employee to the
arc. In estimating available heat energy, the employer must
make some reasonable assumptions about how far the employee will be
from the electric arc. Table 4 lists reasonable distances from the
employee to the electric arc. The distances in Table 4 are
consistent with national consensus standards, such as the Institute
of Electrical and Electronic Engineers' National Electrical
Safety Code, ANSI/IEEE C2-2012, and IEEE Guide for
Performing Arc-Flash Hazard Calculations, IEEE Std 1584b-2011.
The employer is free to use other reasonable distances, but must
consider equipment enclosure size and the working distance to the
employee in selecting a distance from the employee to the arc. The
Occupational Safety and Health Administration will consider a
distance reasonable when the employer bases it on equipment size
and working distance.
Table 4 - Selecting a Reasonable Distance
from the Employee to the Electric Arc
| Class of equipment |
Single-phase arc mm
(inches) |
Three-phase arc mm
(inches) |
| Cable |
NA * |
455 (18) |
| Low voltage MCCs
and panelboards |
NA |
455 (18) |
| Low-voltage
switchgear |
NA |
610 (24) |
| 5-kV
switchgear |
NA |
910 (36) |
| 15-kV
switchgear |
NA |
910 (36) |
| Single conductors
in air (up to 46 kilovolts), work with rubber insulating
gloves |
380 (15) |
NA |
| Single conductors
in air, work with live-line tools and live-line barehand work |
MAD−(2 × kV × 2.54)
(MAD−(2 × kV/10)) † |
NA |
Selecting a reasonable arc gap. For a single-phase arc in
air, the electric arc will almost always occur when an energized
conductor approaches too close to ground. Thus, an employer can
determine the arc gap, or arc length, for these exposures by the
dielectric strength of air and the voltage on the line. The
dielectric strength of air is approximately 10 kilovolts for every
25.4 millimeters (1 inch). For example, at 50 kilovolts, the arc
gap would be 50 ÷ 10 × 25.4 (or 50 × 2.54), which equals 127
millimeters (5 inches).
For three-phase arcs in open air and in enclosures, the arc gap
will generally be dependent on the spacing between parts energized
at different electrical potentials. Documents such as IEEE Std
1584b-2011 provide information on these distances. Employers may
select a reasonable arc gap from Table 5, or they may select any
other reasonable arc gap based on sparkover distance or on the
spacing between (1) live parts at different potentials or (2) live
parts and grounded parts (for example, bus or conductor spacings in
equipment). In any event, the employer must use an estimate that
reasonably resembles the actual exposures faced by the
employee.
Table 5 - Selecting a Reasonable Arc
Gap
| Class of equipment |
Single-phase arc mm
(inches) |
Three-phase arc mm
1
(inches) |
| Cable |
NA 2 |
13 (0.5) |
| Low voltage MCCs
and panelboards |
NA |
25 (1.0) |
| Low-voltage
switchgear |
NA |
32 (1.25) |
| 5-kV
switchgear |
NA |
104 (4.0) |
| 15-kV
switchgear |
NA |
152 (6.0) |
| Single conductors
in air, 15 kV and less |
51 (2.0) |
Phase conductor
spacings. |
| Single conductor
in air, more than 15 kV |
Voltage in kV × 2.54 |
|
|
(Voltage in kV × 0.1), but no
less than 51 mm (2 inches) |
Phase conductor
spacings. |
Making estimates over multiple system areas. The employer
need not estimate the heat-energy exposure for every job task
performed by each employee. Paragraph (g)(2) of § 1926.960 permits
the employer to make broad estimates that cover multiple system
areas provided that: (1) The employer uses reasonable assumptions
about the energy-exposure distribution throughout the system, and
(2) the estimates represent the maximum exposure for those areas.
For example, the employer can use the maximum fault current and
clearing time to cover several system areas at once.
Incident heat energy for single-phase-to-ground
exposures. Table 6 and Table 7 provide incident heat energy
levels for open-air, phase-to-ground electric-arc exposures typical
for overhead systems. 2 Table 6 presents estimates of available
energy for employees using rubber insulating gloves to perform work
on overhead systems operating at 4 to 46 kilovolts. The table
assumes that the employee will be 380 millimeters (15 inches) from
the electric arc, which is a reasonable estimate for rubber
insulating glove work. Table 6 also assumes that the arc length
equals the sparkover distance for the maximum transient overvoltage
of each voltage range. 3 To use the table, an employer would use
the voltage, maximum fault current, and maximum clearing time for a
system area and, using the appropriate voltage range and
fault-current and clearing-time values corresponding to the next
higher values listed in the table, select the appropriate heat
energy (4, 5, 8, or 12 cal/cm 2) from the table. For example, an
employer might have a 12,470-volt power line supplying a system
area. The power line can supply a maximum fault current of 8
kiloamperes with a maximum clearing time of 10 cycles. For rubber
glove work, this system falls in the 4.0-to-15.0-kilovolt range;
the next-higher fault current is 10 kA (the second row in that
voltage range); and the clearing time is under 18 cycles (the first
column to the right of the fault current column). Thus, the
available heat energy for this part of the system will be 4 cal/cm
2 or less (from the column heading), and the employer could select
protection with a 5-cal/cm 2 rating to meet § 1926.960(g)(5).
Alternatively, an employer could select a base incident-energy
value and ensure that the clearing times for each voltage range and
fault current listed in the table do not exceed the corresponding
clearing time specified in the table. For example, an employer that
provides employees with arc-flash protective equipment rated at 8
cal/cm 2 can use the table to determine if any system area exceeds
8 cal/cm 2 by checking the clearing time for the highest fault
current for each voltage range and ensuring that the clearing times
do not exceed the values specified in the 8-cal/cm 2 column in the
table.
2 The Occupational Safety and Health Administration used metric
values to calculate the clearing times in Table 6 and Table 7. An
employer may use English units to calculate clearing times instead
even though the results will differ slightly.
3 The Occupational Safety and Health Administration based this
assumption, which is more conservative than the arc length
specified in Table 5, on Table 410-2 of the 2012 NESC.
Table 7 presents similar estimates for employees using live-line
tools to perform work on overhead systems operating at voltages of
4 to 800 kilovolts. The table assumes that the arc length will be
equal to the sparkover distance 4 and that the employee will be a
distance from the arc equal to the minimum approach distance minus
twice the sparkover distance.
4 The dielectric strength of air is about 10 kilovolts for every
25.4 millimeters (1 inch). Thus, the employer can estimate the arc
length in millimeters to be the phase-to-ground voltage in
kilovolts multiplied by 2.54 (or voltage (in kilovolts) ×
2.54).
The employer will need to use other methods for estimating
available heat energy in situations not addressed by Table 6 or
Table 7. The calculation methods listed in Table 2 and the guidance
provided in Table 3 will help employers do this. For example,
employers can use IEEE Std 1584b-2011 to estimate the available
heat energy (and to select appropriate protective equipment) for
many specific conditions, including lower-voltage, phase-to-phase
arc, and enclosed arc exposures.
Table 6 - Incident Heat Energy for Various
Fault Currents, Clearing Times, and Voltages of 4.0 to 46.0 kV:
Rubber Insulating Glove Exposures Involving Phase-to-Ground Arcs in
Open Air Only * † ‡
| Voltage range
(kV) ** |
Fault current
(kA) |
Maximum clearing
time (cycles) |
| 4 cal/cm 2 |
5 cal/cm 2 |
8 cal/cm 2 |
12 cal/cm 2 |
| 4.0 to 15.0 |
5 |
46 |
58 |
92 |
138 |
|
10 |
18 |
22 |
36 |
54 |
|
15 |
10 |
12 |
20 |
30 |
|
20 |
6 |
8 |
13 |
19 |
| 15.1 to 25.0 |
5 |
28 |
34 |
55 |
83 |
|
10 |
11 |
14 |
23 |
34 |
|
15 |
7 |
8 |
13 |
20 |
|
20 |
4 |
5 |
9 |
13 |
| 25.1 to 36.0 |
5 |
21 |
26 |
42 |
62 |
|
10 |
9 |
11 |
18 |
26 |
|
15 |
5 |
6 |
10 |
16 |
|
20 |
4 |
4 |
7 |
11 |
| 36.1 to 46.0 |
5 |
16 |
20 |
32 |
48 |
|
10 |
7 |
9 |
14 |
21 |
|
15 |
4 |
5 |
8 |
13 |
|
20 |
3 |
4 |
6 |
9 |
Table 7 - Incident Heat Energy for Various
Fault Currents, Clearing Times, and Voltages: Live-Line Tool
Exposures Involving Phase-to-Ground Arcs in Open Air Only * † ‡
#
Voltage range
(kV) ** |
Fault current
(kA) |
Maximum clearing
time (cycles) |
| 4 cal/cm 2 |
5 cal/cm 2 |
8 cal/cm 2 |
12 cal/cm 2 |
| 4.0 to 15.0 |
5 |
197 |
246 |
394 |
591 |
|
10 |
73 |
92 |
147 |
220 |
|
15 |
39 |
49 |
78 |
117 |
|
20 |
24 |
31 |
49 |
73 |
| 15.1 to 25.0 |
5 |
197 |
246 |
394 |
591 |
|
10 |
75 |
94 |
150 |
225 |
|
15 |
41 |
51 |
82 |
122 |
|
20 |
26 |
33 |
52 |
78 |
| 25.1 to 36.0 |
5 |
138 |
172 |
275 |
413 |
|
10 |
53 |
66 |
106 |
159 |
|
15 |
30 |
37 |
59 |
89 |
|
20 |
19 |
24 |
38 |
58 |
| 36.1 to 46.0 |
5 |
129 |
161 |
257 |
386 |
|
10 |
51 |
64 |
102 |
154 |
|
15 |
29 |
36 |
58 |
87 |
|
20 |
19 |
24 |
38 |
57 |
| 46.1 to 72.5 |
20 |
18 |
23 |
36 |
55 |
|
30 |
10 |
13 |
20 |
30 |
|
40 |
6 |
8 |
13 |
19 |
|
50 |
4 |
6 |
9 |
13 |
| 72.6 to 121.0 |
20 |
10 |
12 |
20 |
30 |
|
30 |
6 |
7 |
11 |
17 |
|
40 |
4 |
5 |
7 |
11 |
|
50 |
3 |
3 |
5 |
8 |
| 121.1 to
145.0 |
20 |
12 |
15 |
24 |
35 |
|
30 |
7 |
9 |
15 |
22 |
|
40 |
5 |
6 |
10 |
15 |
|
50 |
4 |
5 |
8 |
11 |
| 145.1 to
169.0 |
20 |
12 |
15 |
24 |
36 |
|
30 |
7 |
9 |
15 |
22 |
|
40 |
5 |
7 |
10 |
16 |
|
50 |
4 |
5 |
8 |
12 |
| 169.1 to
242.0 |
20 |
13 |
17 |
27 |
40 |
|
30 |
8 |
10 |
17 |
25 |
|
40 |
6 |
7 |
12 |
17 |
|
50 |
4 |
5 |
9 |
13 |
| 242.1 to
362.0 |
20 |
25 |
32 |
51 |
76 |
|
30 |
16 |
19 |
31 |
47 |
|
40 |
11 |
14 |
22 |
33 |
|
50 |
8 |
10 |
16 |
25 |
| 362.1 to
420.0 |
20 |
12 |
15 |
25 |
37 |
|
30 |
8 |
10 |
15 |
23 |
|
40 |
5 |
7 |
11 |
16 |
|
50 |
4 |
5 |
8 |
12 |
| 420.1 to
550.0 |
20 |
23 |
29 |
47 |
70 |
|
30 |
14 |
18 |
29 |
43 |
|
40 |
10 |
13 |
20 |
30 |
|
50 |
8 |
9 |
15 |
23 |
| 550.1 to
800.0 |
20 |
25 |
31 |
50 |
75 |
|
30 |
15 |
19 |
31 |
46 |
|
40 |
11 |
13 |
21 |
32 |
|
50 |
8 |
10 |
16 |
24 |
B. Selecting Protective Clothing and Other Protective Equipment
Paragraph (g)(5) of § 1926.960 requires employers, in certain
situations, to select protective clothing and other protective
equipment with an arc rating that is greater than or equal to the
incident heat energy estimated under § 1926.960(g)(2). Based on
laboratory testing required by ASTM F1506-10a, the expectation is
that protective clothing with an arc rating equal to the estimated
incident heat energy will be capable of preventing second-degree
burn injury to an employee exposed to that incident heat energy
from an electric arc. Note that actual electric-arc exposures may
be more or less severe than the estimated value because of factors
such as arc movement, arc length, arcing from reclosing of the
system, secondary fires or explosions, and weather conditions.
Additionally, for arc rating based on the fabric's arc thermal
performance value 5 (ATPV), a worker exposed to incident energy at
the arc rating has a 50-percent chance of just barely receiving a
second-degree burn. Therefore, it is possible (although not likely)
that an employee will sustain a second-degree (or worse) burn
wearing clothing conforming to § 1926.960(g)(5) under certain
circumstances. However, reasonable employer estimates and
maintaining appropriate minimum approach distances for employees
should limit burns to relatively small burns that just barely
extend beyond the epidermis (that is, just barely a second-degree
burn). Consequently, protective clothing and other protective
equipment meeting § 1926.960(g)(5) will provide an appropriate
degree of protection for an employee exposed to electric-arc
hazards.
5 ASTM F1506-10a defines “arc thermal performance value” as “the
incident energy on a material or a multilayer system of materials
that results in a 50% probability that sufficient heat transfer
through the tested specimen is predicted to cause the onset of a
second-degree skin burn injury based on the Stoll [footnote] curve,
cal/cm 2.” The footnote to this definition reads: “Derived from:
Stoll, A.M., and Chianta, M.A., `Method and Rating System for
Evaluations of Thermal Protection,' Aerospace Medicine, Vol 40,
1969, pp. 1232-1238 and Stoll A.M., and Chianta, M.A., `Heat
Transfer through Fabrics as Related to Thermal Injury,'
Transactions - New York Academy of Sciences, Vol 33(7), Nov. 1971,
pp. 649-670.”
Paragraph (g)(5) of § 1926.960 does not require arc-rated
protection for exposures of 2 cal/cm 2 or less. Untreated cotton
clothing will reduce a 2-cal/cm 2 exposure below the 1.2- to
1.5-cal/cm 2 level necessary to cause burn injury, and this
material should not ignite at such low heat energy levels. Although
§ 1926.960(g)(5) does not require clothing to have an arc rating
when exposures are 2 cal/cm 2 or less, § 1926.960(g)(4) requires
the outer layer of clothing to be flame resistant under certain
conditions, even when the estimated incident heat energy is less
than 2 cal/cm 2, as discussed later in this appendix. Additionally,
it is especially important to ensure that employees do not wear
undergarments made from fabrics listed in the note to §
1926.960(g)(3) even when the outer layer is flame resistant or arc
rated. These fabrics can melt or ignite easily when an electric arc
occurs. Logos and name tags made from non-flame-resistant material
can adversely affect the arc rating or the flame-resistant
characteristics of arc-rated or flame-resistant clothing. Such
logos and name tags may violate § 1926.960(g)(3), (g)(4), or
(g)(5).
Paragraph (g)(5) of § 1926.960 requires that arc-rated
protection cover the employee's entire body, with limited
exceptions for the employee's hands, feet, face, and head.
Paragraph (g)(5)(i) of § 1926.960 provides that arc-rated
protection is not necessary for the employee's hands under the
following conditions:
| For any estimated
incident heat energy |
When the employee is wearing
rubber insulating gloves with protectors |
| If the estimated
incident heat energy does not exceed 14 cal/cm 2 |
When the employee is wearing
heavy-duty leather work gloves with a weight of at least 407 gm/m
2 (12 oz/yd 2) |
Paragraph (g)(5)(ii) of § 1926.960 provides that arc-rated
protection is not necessary for the employee's feet when the
employee is wearing heavy-duty work shoes or boots. Finally, §
1926.960(g)(5)(iii), (g)(5)(iv), and (g)(5)(v) require arc-rated
head and face protection as follows:
| Exposure |
Minimum head and
face protection |
| None * |
Arc-rated faceshield with a
minimum rating of 8 cal/cm 2 * |
Arc-rated hood or faceshield
with
balaclava |
| Single-phase, open
air |
2-8 cal/cm 2 |
9-12 cal/cm 2 |
13 cal/ 2 or
higher.† |
| Three-phase |
2-4 cal/cm 2 |
5-8 cal/cm 2 |
9 cal/cm 2 or
higher.‡ |
IV. Protection Against Ignition
Paragraph (g)(3) of § 1926.960 prohibits clothing that could
melt onto an employee's skin or that could ignite and continue to
burn when exposed to flames or to the available heat energy
estimated by the employer under § 1926.960(g)(2). Meltable fabrics,
such as acetate, nylon, polyester, and polypropylene, even in
blends, must be avoided. When these fibers melt, they can adhere to
the skin, thereby transferring heat rapidly, exacerbating burns,
and complicating treatment. These outcomes can result even if the
meltable fabric is not directly next to the skin. The remainder of
this section focuses on the prevention of ignition.
Paragraph (g)(5) of § 1926.960 generally requires protective
clothing and other protective equipment with an arc rating greater
than or equal to the employer's estimate of available heat energy.
As explained earlier in this appendix, untreated cotton is usually
acceptable for exposures of 2 cal/cm 2 or less. 6 If the exposure
is greater than that, the employee generally must wear
flame-resistant clothing with a suitable arc rating in accordance
with § 1926.960(g)(4) and (g)(5). However, even if an employee is
wearing a layer of flame-resistant clothing, there are
circumstances under which flammable layers of clothing would be
uncovered, and an electric arc could ignite them. For example,
clothing ignition is possible if the employee is wearing flammable
clothing under the flame-resistant clothing and the underlayer is
uncovered because of an opening in the flame-resistant clothing.
Thus, for purposes of § 1926.960(g)(3), it is important for the
employer to consider the possibility of clothing ignition even when
an employee is wearing flame-resistant clothing with a suitable arc
rating.
6 See § 1926.960(g)(4)(i), (g)(4)(ii), and (g)(4)(iii) for
conditions under which employees must wear flame-resistant clothing
as the outer layer of clothing even when the incident heat energy
does not exceed 2 cal/cm 2.
Under § 1926.960(g)(3), employees may not wear flammable
clothing in conjunction with flame-resistant clothing if the
flammable clothing poses an ignition hazard. 7 Although outer
flame-resistant layers may not have openings that expose flammable
inner layers, when an outer flame-resistant layer would be unable
to resist breakopen, 8 the next (inner) layer must be
flame-resistant if it could ignite.
7 Paragraph (g)(3) of § 1926.960 prohibits clothing that could
ignite and continue to burn when exposed to the heat energy
estimated under paragraph (g)(2) of that section.
8 Breakopen occurs when a hole, tear, or crack develops in the
exposed fabric such that the fabric no longer effectively blocks
incident heat energy.
Non-flame-resistant clothing can ignite even when the heat
energy from an electric arc is insufficient to ignite the clothing.
For example, nearby flames can ignite an employee's clothing; and,
even in the absence of flames, electric arcs pose ignition hazards
beyond the hazard of ignition from incident energy under certain
conditions. In addition to requiring flame-resistant clothing when
the estimated incident energy exceeds 2.0 cal/cm 2, §
1926.960(g)(4) requires flame-resistant clothing when: The employee
is exposed to contact with energized circuit parts operating at
more than 600 volts (§ 1926.960(g)(4)(i)), an electric arc could
ignite flammable material in the work area that, in turn, could
ignite the employee's clothing (§ 1926.960(g)(4)(ii)), and molten
metal or electric arcs from faulted conductors in the work area
could ignite the employee's clothing (§ 1926.960(g)(4)(iii)). For
example, grounding conductors can become a source of heat energy if
they cannot carry fault current without failure. The employer must
consider these possible sources of electric arcs 9 in determining
whether the employee's clothing could ignite under §
1926.960(g)(4)(iii).
9 Static wires and pole grounds are examples of grounding
conductors that might not be capable of carrying fault current
without failure. Grounds that can carry the maximum available fault
current are not a concern, and employers need not consider such
grounds a possible electric arc source.
HOISTS MUST BE
ELECTRONICALLY ISOLATED FROM SCAFFOLD 
[61 FR 46122, Aug.
30, 1996; 61 FR 59832, Nov. 25, 1996; 85 FR 8736, Feb. 18, 2020]
