Demolition
The primary hazards associated with demolition are (1) falls
from elevated work surfaces; (2) exposure to hazardous air
contaminants; (3) being struck by falling or collapsing structures;
and (4) electrical hazards. Regulations to address these hazards
include the following:
A. A DOSH permit is required for demolition of structures
(buildings) more than 36 ft. high. 341(a)(3)
B. A predemolition survey must be made to determine whether
the planned work will cause:
- Any structure to collapse. 1734(b)(1)
- Worker exposure to asbestos. 1529(k)(1),
1735(b)
- Worker exposure to lead. 1532.1(d)(1)
C. Utilities to the structure being demolished must be turned
off or protected from damage. 1735(a)
D. Demolition techniques include the following:
- Entrances to multi-story buildings must be protected
by a sidewalk shed or a canopy. 1735(j)
- The demolition work on floors and exterior walls must
progress from top to bottom. 1735(f)(1)
Exception: Demolition with explosives and for cutting
chute holes is not required to progress from top to bottom.
1735(f)(1)
- The employer must check continually for hazards created
by weakening of the structure’s members. If a hazard
occurs, it must be removed before workers may continue.
1735(d)(4)
- Floor openings must have curbs and stop logs to prevent
equipment from running over the edge. 1735(v)
- Wall openings must be guarded except on the ground floor
and the floor being demolished. 1735(k)
- Walkways 20 in. wide must be provided as a means of access
across joists, beams, or girders. 1735(h)
- Demolition debris must be kept wet to prevent dust from
rising. 1735(t)
- Whenever waste material is dropped to any point lying
outside the exterior walls of the building, enclosed chutes
shall be used unless the area is effectively protected by
barricades, fences, or equivalent means. Signs shall be
posted to warn employees of the hazards of falling debris.
1736(a)
- Chutes or chute sections that are at an angle of more
than 45° from the horizontal must be entirely enclosed
except for openings equipped with closures at or about floor
level for the insertion of materials. 1736(f)
- When chutes are used to load trucks, they must be fully
enclosed. Gates must be installed in each chute at or near
the discharge end. A qualified person must be assigned to
control the operation of the gate and the backing and loading
of trucks. 1736(b)
- Any chute opening into which employees dump debris by
hand must be protected by a guardrail. 1736(d)
- When debris is dropped through holes in a floor without
the use of chutes, the area onto which the material is dropped
shall be completely enclosed with barricades not less than
42 in. high and not less than 6 ft. back from the projected
edge of the opening above. Signs that warn of the hazard
of falling materials shall be posted at each level. Removal
of debris shall not be permitted in the lower drop area
until handling of debris ceases above. 1736(f)
E. Crane demolition work is guided by these regulations:
4941
- The wrecking ball’s weight must not exceed 50% of
the clamshell rating or 25% of the rope-breaking strength.
4941(a)
- The swing of the boom should be limited to 30° left
or right. 4941(b)
- The wrecking ball must be attached with a swivel-type
connection. 4941(b)
- The load line and ball must be inspected at least twice
each shift. 4941(c)
- Outriggers are required when using a wrecking ball (truck
cranes). 4941(d)
Note: See crane standards on pages
37-44. Group
13 in the GISOs
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