TO: |
All MOSH Personnel |
|
|
FROM: |
Cheryl Kammerman, Assistant Commissioner |
|
|
SUBJECT: |
Interim Inspection Procedures During Communication
Tower Construction Activities |
|
|
REFERENCE: |
OSHA CPL
2-1.29 |
|
|
EFFECTIVE DATE: |
April 12, 2001 |
|
|
DATE: |
February 28, 2002 |
|
|
A. Purpose:
This instruction establishes the inspection policy and procedures
to ensure uniform enforcement by field enforcement personnel of
the provisions addressing fall protection and safe access to communications
towers during construction. This instruction applies only to the
construction of new communications towers and not activities such
as maintenance, retrofitting, and dismantling.
B. Background:
Accessing towers by the use of fixed ladders with attached climbing
devices has been the preferred method as it provides conventional
fall protection during ascent and descent of the structure. Some
representatives of the tower construction industry assert that
continual climbing of high towers is physically demanding and
can lead to stress and medical ailments over an extended period
of time and may contribute to other safety problems including
falls. To alleviate these problems, the industry has asked that
employees be allowed to ride a hoist line to work stations on
towers. Since OSHA does not specifically address tower erection
under its current standards but wishes to help reduce the accident
and injury rates associated with tower erection, OSHA believes
that the methods in Appendix A represent the best practices which
can be implemented to safeguard employees while being hoisted
to work stations on the tower. If new information shows that these
practices need to be changed, OSHA/MOSH will revise this directive
accordingly.
C. Action:
1. Compliance
and Consultation Supervisors shall ensure that training sessions
are conducted on the contents of this Instruction.
- The Assistant
Commissioner or authorized representative shall ensure compliance
with the attached guidelines for enforcement.
- Compliance
Guidelines for Fall Protection and Employee Access by Hoist
During Communication Tower Construction Activities.
- For purposes
of this directive, OSHA/MOSH agrees that the hoist line may
be used to hoist employees for access to tower work stations
over 200 feet in height if the work practices and requirements
set out in Appendix A are followed. At heights of 200 feet
and below, employees may not be hoisted to their work stations
using the hoist line.
When climbing
the tower during construction activities, employees must be
protected from falls using a fall arrest system meeting the
criteria of 1926.502 or a ladder assist safety device meeting
the requirements of 1926.1053(a). These are acceptable methods
of accessing tower work stations regardless of height. All employees
climbing or otherwise accessing towers must be trained in the
recognition and avoidance of fall hazards and in the use of
the fall protection systems to be used, pursuant to 1926.21
or where applicable, 1926.1060.
- Citation Guidelines
- For hazards
associated with falls once employees are at their workstation
at levels in excess of 25 feet, employers who fail to provide
fall protection shall be cited under 1926.105(a).
- Whenever an
employer fails to follow the guidelines set forth in Appendix
A, citations shall be issued under the applicable provisions
of subpart N and, in the alternative, section 5-104(a) of
the Act (the general duty clause) for hazards associated with
work practices and equipment used to hoist employees on load
lines to gain access to towers.
APPENDIX
A
Compliance
Guidelines for Employee Access by Hoist During Communication Tower
Construction Activities
Definitions
Crew Chief: One
who is authorized, designated, deemed competent and qualified
by the employer.
Anti-Two Blocking: A positive acting device which prevents contact
between the load block or overhaul ball and the top block (two-blocking),
or a system which deactivates the hoisting action before damage
occurs in the event of a two-block situation.
Maximum Intended Load: The total load of all employees, tools,
materials, load lines and other loads reasonably anticipated to
be applied to the hoist apparatus when an employee is hoisted.
Competent Person: One who is capable of identifying existing and
predictable hazards in the surroundings or working conditions
which are unsanitary, hazardous, or dangerous to employees and
who has authorization to take prompt corrective measures to eliminate
problems.
Authorized Person: A person approved or assigned by the employer
to perform a specific type of duty or duties or to be at a specific
location or locations at the job site.
Qualified: One who, by possession of a recognized degree, certificate
or professional standing, or who by extensive knowledge, training
and experience, has successfully demonstrated the ability to solve
or resolve problems relating to the subject matter, the work or
the project.
Gin Pole: A device attached to the tower used to raise sections
of tower steel or equipment into position.
Specific
Requirements.
Employees may be hoisted on the hoist line to reach work stations
at heights greater than 200 feet only if all of the following
conditions are met. The Agency believes that strict adherence
to the guidelines set forth in this Appendix will provide employers
with the appropriate safety measures for access during tower erection.
Riding the hoist line to work stations at heights less than 200
feet is not permitted.
1. Training.
Before an employee is allowed to perform any job related to hoisting
employees aloft for tower work, the employee shall receive training
on safe access pursuant to these guidelines. The operator of the
hoist shall have a thorough understanding of these guidelines
pertaining to hoisting employees on the hoist line.
2. Equipment.
- An anti-two
block device shall be used on all hoists, except where an
employer can demonstrate that ambient radiation frequency
(RF) precludes that use. In such case, a site specific program
will be established and maintained on site to ensure that
two blocking cannot occur and that effective communication
between the hoist operator and personnel being hoisted is
maintained. This program could include a cable marking system,
an employee situated on the tower in a position to observe
the top block, or any other system which will adequately ensure
communication.
- The rigging,
hoist line and slings shall have a factor of safety of 10
against failure during personnel lift(s).
- The hoist line
used to raise or lower employees shall be equipped with a
swivel to prevent any rotation of the employees.
- The use of
spin-resistant wire rope is prohibited when hoisting employees.
- When hoisting
personnel (versus material) the hoist capacity load rating
shall be derated by a factor of 2 (reduced by half).
- All employees
shall be provided with and required to use the proper personal
protective equipment (including fall protection equipment)
which shall be inspected before each lift.
- Except where
the employer can demonstrate that specific circumstances or
conditions preclude its use, a guide line (tag line) shall
be used to prevent the employees or the platform from contacting
the tower during hoisting.
- The gin pole
shall be thoroughly inspected before use by a competent person
to determine that it is free from defects, including but not
limited to: damaged and/or missing members; corrosive damage;
missing fasteners and broken welds at joints; and general
deterioration.
- The gin pole
shall be attached to the tower as designed by a registered
professional engineer. There shall be a minimum of two attachment
locations: at the bottom of the gin pole and near the top
of the tower being erected.
- The personnel
load capacity and material capacity of the lifting system
in use shall be posted at the site near the location of the
hoist operator. If the system is changed (for example, if
the gin pole angle is changed), the posted capacity shall
be changed accordingly.
3. Trial Lift
and Proof Testing.
- A trial lift
of the maximum intended personnel load shall be made from
ground level to the location to which personnel are to be
hoisted.
- The trial lift
shall be made immediately prior to placing personnel on the
hoist line. The hoist operator shall determine that all systems,
controls and safety devices are activated and functioning
properly. A single trial lift may be performed for all locations
that are to be reached from a single set-up position. The
hoist operator shall determine that no interference exists
and that all configurations necessary to reach those work
locations remain under the limit of the hoist's rated capacity
as identified in paragraph 2(e), and additionally maintain
a 10:1 factor of safety against failure.
- The trial lift
shall be repeated prior to hoisting employees whenever the
hoist is moved and set up in a new location or returned to
a previously used position.
- After the trial
lift, employees shall not be lifted unless the following conditions
are met:
(1) Hoist wire
ropes are determined to be free of damage in accordance with
the provisions of 29 CFR 1926.550;
(2) Multiple part lines are not twisted around each other;
and,
(3) The proof testing requirements have been satisfied.
- If the hoist
wire rope is slack, the hoisting system shall be inspected
to ensure that all wire ropes are properly seated on drums
and in sheaves.
- A visual inspection
of the hoist, rigging, base support and foundation
shall be made by a competent person immediately after the
trial lift to determine whether testing has exposed any defect
or adverse effect upon any component of the structure.
- Any defects
found during the inspection which may create a safety hazard
shall be corrected, and another trial lift shall be performed
before hoisting personnel.
- Prior to hoisting
employees and after any repair or modification, the personnel
rigging shall be proof tested to 125% of the greatest anticipated
load by holding it in a suspended position for five minutes
with the test load evenly distributed (this may be done concurrently
with the trial lift). After proof testing, a competent person
shall inspect the rigging. Any deficiencies found shall be
corrected and another proof test shall be conducted.
4. Pre-Lift
Meeting.
-
A pre-lift meeting shall be held prior to the trial lift at
each location.
-
The pre-lift meeting shall:
(1)
be attended by the hoist operator, employees to be lifted, and
the crew chief;
(2) review the procedures to be followed and all appropriate
requirements contained in this guideline; and
(3) be repeated for any employee newly assigned to the operation.
5. Documentation.
- All trial lifts,
inspections and proof tests shall be documented, and the documentation
shall remain on site during the entire length of the project.
- The pre-lift
meeting shall be documented, and the documentation shall remain
on site during the entire length of the project.
6. Hoisting
an Employee to the Work Station.
-
Except where an employer can demonstrate that specific circumstances
or conditions preclude its use, a personnel platform must
be used to hoist more than one employee to the work station.
That personnel platform must meet the requirements of 29 CFR
1926.550 (g). When a personnel platform cannot be used, the
provisions in paragraph b below must be followed.
- When a boatswains
seat-type or full body seat harness is used to hoist employees,
the following shall apply:
- No more than
two employees may be hoisted at a time;
- The employee's
harness shall be attached to the hook by a lanyard meeting
the strength requirements of 29 CFR 1926.502;
- Only locking-type
snap hooks shall be used; and
- The harness
shall be equipped with two side rings and at least one front
and one back D ring.
- The hoist line
hook shall be equipped with a safety latch which can be locked
in a closed position to prevent loss of contact.
- The maximum
rate of travel shall not exceed 200 feet per minute when a
guide line is used to control personnel hoists. When a guide
line cannot be used, the rate of travel of the employee being
hoisted shall not exceed 100 feet per minute. In all personnel
hoist situations, the maximum rate shall not exceed 50 feet
per minute when personnel being lifted approach to within
50 feet of the top block.
- The use of
free-spooling (friction lowering) is prohibited.
- When the hoist
line is being used to raise or lower employee(s), there shall
be no other load attached to any hoist line, and no other
load shall be raised or lowered at the same time on the same
hoist.
- As-built drawings
approved by a registered professional engineer shall provide
the lifting capacity of the gin pole and shall be available
at the job site.
- The gin pole
raising line shall not be used to raise or lower employees.
- Employees must
maintain 100% tie-off while moving between the hoist line
and the tower.
7. Communication
Between the Hoist Operator and Hoisted Employees.
- Employees being
hoisted shall remain in continuous sight of and/or in direct
communication with the operator or signal person. In those
situations where direct visual contact with the operator is
not possible and the use of a signal person would create a
greater hazard for the person being hoisted, direct communication
alone, such as by radio, shall be used.
- When radios
are used, they shall be non-trunking closed 2-way selective
frequency radio systems.
- When hand signals
are used, the employees must use industry standardized hand
signals as required by 1926.550(a)(4).
8. Weather
Conditions/Energized Power Lines.
-
Employees shall not be hoisted during adverse weather conditions
(high winds, electrical storms, snow, ice, sleet), or other
impending danger, except in the case of emergency employee
rescue. This determination shall be made by the competent
person.
-
The hoist system (gin pole and its base hoists) used to raise
and lower employees on the hoist line, shall not be used unless
the following clearance distances as recommended by ANSI are
maintained at all times during the lift:
Power line voltage
phase to phase (kV)
|
Minimum safe
clearance (feet)
|
50 or below
|
10
|
Above 50 to 200 |
15 |
Above 200 to 350
|
20
|
Above 350 to 500
|
25
|
Above 500 to 750
|
35
|
Above 750 to 1,000
|
45
|
9. Hydraulic
Hoists (Drum Hoists).
- The hoist used
for personnel lifting shall meet the applicable requirements
for design, construction, installation, testing, inspection,
maintenance, modification, repair and operations as referenced
in this Appendix and as prescribed by the manufacturer. Where
manufacturers' specifications are not available, the limitations
assigned to the equipment shall be based on the determinations
of a registered professional engineer.
- The hoist shall
be positioned so that it is level and the distance between
the drum and the foot block at the base of the tower will
allow proper spooling of wire rope.
- The foot block
shall be anchored to prevent displacement and be supported
to maintain proper alignment.
- The hoist shall
be designed to lift materials and personnel with the same
drum or drums.
- Any hoist that
has been modified or repaired must be proof-tested to 125%
of its rated capacity.
- Rated load
capacities, recommended operating speeds, and special hazard
warnings or instructions shall be conspicuously posted on
all hoists.
- Belts, gears,
shafts, pulleys, sprockets, spindles, drums, fly wheels, chains
or other rotating parts, where exposed, shall be totally enclosed.
- Personnel load
capacity for the current configuration of the gin pole shall
be posted within sight of the hoist operator.
- The hoist shall
have an hour meter and a line speed limiter.
- The hoist shall
be designed for and must use powered lowering.
- The alignment
of hoist components shall be maintained within manufacturer's
specified limits that prevent premature deterioration of gear
teeth, bearings, splines, bushings, and any other parts of
the hoist mechanism.
- All exhaust
pipes shall be guarded where exposed.
- An accessible
fire extinguisher of 5BC rating or higher shall be available
at the operator's station.
- The hoist shall
be serviced and maintained per the manufacturer's recommendations.
- The operating
manual developed by the manufacturer for the specific make
and model hoist being used shall be maintained at the site
at all times.
- A hoist log
book shall be used to record all hoist inspections, tests,
maintenance and repair. The log shall be updated daily as
the hoist is being used and shall be signed by the operator
and/or crew chief. Service mechanics shall sign the log after
conducting maintenance and repair. The log shall be maintained
at the site.
10. Hoist
Mounting.
- The hoist shall
be installed following the manufacturer's mounting procedure
to prevent excessive distortion of the hoist base as it is
attached to the mounting surface. Flatness of the mounting
surface shall be held to tolerances specified by the hoist
manufacturer.
- The hoist shall
be anchored so as to resist at least two times any reaction
induced at the maximum attainable line pull and shall be anchored
so that the hoist will not twist or turn.
- If the hoist
is mounted to a truck chassis, it shall be properly aligned
and anchored in at least two corners to prevent movement,
and the wheels shall be properly chocked.
11. Drums.
- The hoist drum
shall be capable of raising or lowering 125% of the rated
load of the hoist.
- The hoist drum
shall have a positive means of attaching the wire rope to
the drum.
- There shall
always be at least three full wraps of wire rope on the hoist
drum when personnel are being hoisted.
- During operation,
the flange shall be two times the wire rope diameter higher
than the top layer of wire rope at all times.
12. Brakes
and Clutches.
- Brakes and
clutches shall be capable of arresting any over-speed descent
of the load.
- The hoist shall
be provided with a primary brake and at least one independent
secondary brake, each capable of stopping and holding 125%
of the lifting capacity of the hoist.
- The primary
brake shall be directly connected to the drive train of the
hoisting machine, and shall not be connected through belts,
chains, clutches or screw-type devices.
- The secondary
brake shall be an automatic emergency-type brake that, if
actuated during each stopping cycle, shall not engage before
the hoist is stopped by the primary brake.
- When a secondary
brake is actuated, it shall stop and hold the load within
a vertical distance of 24 inches.
- Brakes and
clutches shall be adjusted, where necessary, to compensate
for wear and to maintain adequate force on springs where used.
- Powered lowering
must be used.
- When power
brakes having no continuous mechanical linkage between the
actuating and braking mechanism are used for controlling loads,
an automatic means shall be provided to set the brake to prevent
the load from falling in the event of loss of brake actuating
power.
- Static brakes
shall be provided to prevent the drum from rotating in the
lowering direction and shall be capable of holding the rated
load indefinitely without attention from the operator.
- Brakes shall
be automatically applied upon return of the control lever
to its center (neutral) position.
- Brakes applied
on stopped hoist drums shall have sufficient impact capacity
to hold 1.5 times the rated torque of the hoist.
13. Hoist
Controls.
- Power plant
controls shall be within easy reach of the operator and shall
include a means to start and stop, control speed of internal
combustion engines, stop prime mover under emergency conditions,
and shift selective transmissions.
- All controls
used during the normal operation of the hoist shall be located
within easy reach of the operator at the operator's station.
- Controls shall
be clearly marked (or be part of a control arrangement diagram)
and easily visible from the operator's station.
- Foot-operated
pedals, where provided, shall be constructed and maintained
so the operator's feet will not readily slip off and the force
necessary to move the pedals can be easily applied.
- The controls
shall be self-centering controls (i.e., "deadman"
type) that will return the machine to neutral and engage the
drum brakes if the control lever is released.
14. Wire Rope
and Rigging
- All wire rope
and rigging shall be inspected daily before use.
- All eyes in
wire rope slings shall be fabricated with thimbles.
- All eyes in
wire rope slings shall:
(1) Be made
with swaged-type fittings; and,
(2) Be field fabricated by a qualified person or factory made.
15. Hoist
Operator.
- The hoist operator
shall have classroom training, a minimum of 40 hours experience
as a hoist operator, not less than 8 hours experience in the
operation of the specified hoist or one of the same type,
and demonstrated the ability to safely operate the hoist.
- The employer
shall not allow an employee to operate a hoist when that employee
is physically or mentally unfit.
- The hoist operator
shall be responsible for those operations under his/her direct
control. Whenever there is any doubt as to safety, the operator
shall have the authority to stop and refuse to handle the
load until safety has been assured.
- The hoist operator
shall remain at the controls at all times when personnel are
on the hoist line.
- Before starting
the hoist, the operator shall ensure that:
(1) The daily inspection has been conducted;
(2) All controls are in the "off" position; and,
(3) All personnel are in the clear.
16. Hoist
Inspections.
- Routine inspections.
(1) Each day
before use all hoists shall be visually inspected by a qualified
person.
(2) All hoists shall be inspected thoroughly at three month
intervals by a qualified person, as will any hoists that have
been idle for more than one month but less than six months.
Such inspection will include a hands-on operation of all moving
parts to ensure that they are intact and will properly function
before being put into service.
- All hoists
shall undergo a tear-down inspection annually unless the following
conditions exist that allow for less frequent tear-down inspections.
(1) A hoist that has been idle for a period of over six (6) months
shall be given an annual inspection which includes the hoist
being completely disassembled, cleaned and inspected. Parts
such as pins, bearings, shafts, gears, brake plates, etc. found
worn, cracked, corroded, distorted or otherwise non-functional
must be replaced before the hoist is used.
(2) Hoists with infrequent to moderate usage (hoists that have
been used for fifty (50) hours or less per month and normally
operate at considerably less than the hoist rated capacity based
on the average use over a month) may go up to thirty-six (36)
months between tear down inspections if serviced under a preventive
maintenance program (as specified by the manufacturer) that
includes annual hydraulic oil sample analysis. An oil sample
analysis, meaning a laboratory analysis, is used to evaluate
the mechanical integrity of the hoist. Oil in these hoists shall
be changed at least on an annual basis, just after the oil analysis
is performed. Hoists not subjected to recommended oil sample
analysis shall undergo an annual tear-down inspection.
(3) Hoists that experience heavy usage (hoists that are used
for more than fifty (50) hours per month) may go up to twenty-four
(24) months between tear-down inspections if serviced under
a preventive maintenance program as in (2) above.
(4) Any rebuilt hoist assembly must be line pull tested to the
rated load. The hoist drum must be rotated several times in
both raising and lowering directions under full-rated load,
while checking for smooth operation.
|