Transcript Scaffolding Your Key to Stability

Scaffolding: Your Key to
Stability
Presented By: Georgia Tech
Occupational Safety and Health
Program
29 CFR 1926 Subpart L
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1926.450
1926.451
1926.452
1926.453
1926.454
Scope and Application
General Requirements
Additional Requirements
Aerial Lifts
Training Requirements
– Appendices A thru E
Most Frequently Cited Hazards
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Scaffolds above 10 ft.-Fall Protection
Scaffold Access
Scaffold Working Levels-Decked
Aerial Lift-Harness/Lanyard
Training in use of scaffolds
National Statistics
• A significant percentage
of personnel in
construction (65) work
from scaffolds routinely
• There are approximately
50 fatalities related to
scaffolds each year.
• There are approximately
4500 employee injuries
each year as a result of
using scaffolds.
• For the period 1980-1985
falls from scaffolds
accounted for 17% of the
fatalities for falls from
elevations.
Georgia Statistics
• The total number of fall related fatalities in
2000 was 25.
• The number of fatalities involving scaffolds
were 6.
• Falls from scaffolds represented twenty five
percent of the total fatalities in the state
Hazards
• Injured workers revealed that 72% of the
accidents were caused by:
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Platform failure
Support failure
Slipping
Being struck by an object
Requirements for Competent
Person
• A competent person is a person on the
project who has knowledge to identify and
the authority to correct site hazards
– OSHA 10 or 30 hour training card could
support the fact you had training and are
knowledgeable
– The 10 or 30 hour OSHA training card alone
does not necessarily mean you are a competent
person
Requirements for Competent
Person
• Scaffolds have to be inspected daily by a
competent person
• Scaffolds must be erected, moved,
dismantled or altered under the supervision
of a competent person
• Work by qualified workers selected by the
competent person
Capacity 29 CFR 1926.451(a)
• Each scaffold and scaffold component must
be capable of supporting four times the
intended weight.
• Direct connections to the roof and
counterweights of suspended scaffolds must
resist four times the tipping moment or 1.5
times tipping moment imposed by scaffold
operating at stall load
Capacity 29 CFR 1926.451(a)
• Suspension ropes including hardware must
support six times the maximum intended
load
• The stall load of any scaffold hoist shall not
exceed three times its rated load.
• Scaffolds must be designed by a qualified
person and loaded accordingly.
Platform Construction 29 CFR
1926.451(b)
• All working levels of scaffolds are required
to be fully decked.
– No gaps greater than one inch allowed
• Each scaffold platform shall be at least 48
inches wide.
– Ladder jack, roof bracket and pump jack can be
12 inches wide.
Platform Construction 29 CFR
1926.451(b)
• The front edge shall not be more than 14
inches from face (if in excess rails
required).
• The end of each platform will extend over
the center line by six inches (unless
hooked).
Platform Construction
• Requirement for over
hang based on length:
– 10 ft or less platform
not to exceed 12 inches
– More than 10 ft not to
exceed 18 inches
• For extended
platforms overlap over
supports by 12 inches
(unless secured)
• Wood platforms shall
not be covered with
opaque finishes.
• Components
(different) shall not be
mixed unless they fit
(integrity maintained).
Supported Scaffolds, 29 CFR
1926.451(c)
• Scaffolds with a width to height of more
than 4:1 need to be restrained
• Guys, ties, and braces installed in
accordance to manufacturer
• Ties, guys, wires must be used for eccentric
load
Supported Scaffolds, 29 CFR
1926.451(c)
• Supported poles, legs, and posts need to
bear on base plates and mudsills or other
firm foundation.
• Footing must be rigid and sound.
• No unstable objects for supports or
platform.
• Legs, posts, frames must be plumb and
braced to prevent swaying.
Scaffold Access, 29 CFR
1926.451(e)
• When scaffold
platforms are 2 feet
above or below a point
of access ladders, stair
towers or personnel
hoist must be used.
– Cross braces can not be
climbed.
– Ladders set up so not
to tip scaffold.
• Stairway type ladders
can be used in
1926.451(e)(3)
– Railing has to be
provided
• Ramps 1926.451(e)(5)
– Rails over 6 feet
– No slope greater than
20 degrees
Scaffold Access
• Integral prefabricated
scaffold access
frames:
– Designed and
constructed as ladder
rungs
– Rung length of 8
inches
– Uniform space
• Direct Access shall only
be used when scaffold is
not more than 14”
horizontal and 24” vertical
away.
• Safe means of access shall
be provided during
erecting or dismantling as
determined by competent
person.
Scaffold Use 1926.451(f)
• Scaffolds shall not be
excessively loaded
• Inspection by competent
person before each shift
• Damaged scaffold
immediately repaired or
replaced.
• Maintain adequate
distance from power lines
(3 ft for less than 300 V
and 10 ft for greater than
300)
• Must not work on
slippery platforms,
debris or during high
winds.
• Standing on objects to
increase height
prohibited.
• Ladder may be used
on wide area scaffold.
Scaffold Use
• Scaffolds must be inspected before use each
shift by competent person.
• All damaged components must be repaired
or replaced immediately.
Fall Protection, 29 CFR
1926.451(g)
• Required on all
scaffolds greater than
10 feet.
• Boatswains chair,float
scaffold or similar
require fall arrest.
• Suspension scaffold
requires rails and fall
arrest system
(independent life line).
• Rail system design:
– Top rail installed between
38 and 45 inches
– mid rail between top and
working surface
• Finished components
must with stand:
– A force 200 pounds for top
rail
– 150 pounds for mid rail
Fall Protection
• Guardrails must be free of
sharp edges.
• Ends of rails must be
constructed so it does
overhang the terminal
posts
• Steel or plastic bands are
not acceptable as railing
• Cross brace may be used
as a mid rail if it meets the
height requirement (cross
between 20-30 inches)
• Falling object
requirements are:
– Employees on scaffold(in
addition to hard hats) must
be protected by toe boards,
debris nets or canopy
– Area below must be
protected by barricades,
canopies, toe boards on
scaffolds over 10 feet
• Toe boards- withstand 50
pounds of force and be 3.5
inches wide.
Additional Scaffolds-Supported,
29 CFR 1926.452
• Tube and coupler:
– The existing platform
shall not be moved
until bearers are set
– X bracing installation
– Couplers have to made
of structural steel
– Scaffolding over 125
ft. have to be designed
by registered engineer
• Fabricated Frame:
– The existing platform
shall remain until the
frames are set/braced
– Frames and panels
shall be braced (joined
with stack pin
– Scaffolding over 125
ft. have to be designed
by registered engineer
Additional Scaffold-Supported
• Horse scaffolds:
– Limited to two tiers (10 ft.)
– Horses arranged directly
over each other
– Legs nailed down and tiers
braced
• Crawling boards:
– Extend from peak to eaves
and secured to roof by ridge
hooks or equivalent
• Pump jack scaffolds:
– Bracket must have two
positive grips
– Poles secured at the top and
bottom
– Work bench is not a
platform
– Continuous length poles
joined at seam parallel to
bracket
– Mending plates must be
installed at 2X4 splices for
strength
Additional Scaffolds-Supported
• Ladder jack scaffolds:
– Not to exceed 20 feet
– Ladder meet requirement of
part X
– No bridging of platform
– Ladders must be provided
with device to prevent
slipping
– Constructed to bear on side
rails and rungs or rungs (if
rungs at length of 10
inches)
• Window jack scaffold:
– Attached to window
opening and not used to
place planks between
scaffolds
• Step, trestle, and ladder
scaffolds:
– Platform not placed higher
than second highest rung
and ladder secured
– Ladders designed to part X
Additional RequirementsSuspended
• Swing Stages:
– Platform limited to 36”
– Platform must be securely
fastened to hangars
– Platforms shall be of the
ladder, plank, or beam type
– Two point scaffolds shall
not be bridged together
unless bridged and hoist is
appropriately sized
• Multi level scaffolds:
– Equipped with
independent support
lines (equal to number
of suspension points)
and not attached to the
same point as
suspension ropes
– Supports for platform
attached to stirrup only
Additional Requirements-Mobile
• Requirements for mobile
scaffolds:
– Adequately plumbed,
braced, level and squared
– Must have means to lock
wheels/casters
– Force to move scaffold no
higher than 5 feet above
support surface
– Power system must be
designed for scaffold
• Stabilized to prevent tip
• Platform must not extend
base support without
outriggers
• Caster stems-pinned
• Riding not allowed unless:
– surface floor level and free
of debris and 2:1 BXH ratio
– Outriggers on both sides
– No one allowed on
extended platform
Additional Requirement-Stilts
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Only to be used on large area scaffold
Surfaces must be flat and free of pits
No obstructions
Stilts have to be maintained
Guardrails must be raised by an amount
equal to stilts
Requirements for Aerial Lifts
29 CFR 1926.453
• Meet the design criteria of
ANSI
• Aerial ladders must be
secured in lower traveling
position by a locking
device before it is moved.
• Ext./Art. Platforms:
• Boom must be adequately
stowed before move
• Insulated portion must not
be altered
– A body belt or harness and
lanyard must be used
– Employees must stand on
floor of basket
– Never exceed load capacity
– Lift truck shall not be
moved with men in basket
unless adequately designed
(upper controls-personnel
carriers)
– Brakes set for outrigger use
(wheels chock)
Aerial Lifts
• Extensible and articulating platforms:
– Lift controls must be tested each day
– Authorized employees only
– No belting off to adjacent structure
• All pneumatic and hydraulic components
comply with ANSI A92.2-1969 and non
critical parts must have burst factor 2:1.
Training-General
29 CFR 1926.454
• Employees must receive training from
qualified person that includes:
– Nature of electrical, fall, and falling items
– Use of scaffold/handling
– Maximum intended load and load carrying
capabilities of scaffold
– Methods for dealing with electrical hazards
and fall protection system
– Requirements of sub L
Training-Setup or Dismantling
• Employees must be trained in:
– Nature of scaffold hazards
– Procedures for setup, dismantling or moving
the system
– Design criteria, maximum intended load
carrying capacities and use of scaffold
– Requirements of subpart L
Training-Need for Retraining
• When the employer has reason to believe an
employee lacks the skill or understanding needed
for safe work involving scaffolds, retraining shall
be performed until proficiency is regained.
Retraining is required:
– When additional or new hazards exist.
– Changes in the type of scaffold and fall protection exist.
– Where there are inadequacies in an employee’s work.
Resources
• www.osha.gov
– 29 CFR 1926.451
– NAHB-OSHA Job Site Safety Handbook
– Construction Industry Digest
• Scaffolding Industry Association
– www.scaffold.org
• American National Standards Institute
– A92 (SIA): Scaffolds and other elevating devices