Fall arrest safety: OSHA recommends the
following regarding fall arrest systems safety.
• The arresting rope or cable should stop
the fall before the worker reaches any lower
level, but in all cases it shouldn’t extend
more than 6 feet.
• Maximum arresting force is 1,800
pounds (816 kilograms), over a maximum
deceleration distance of 3. 5 feet (1 meter).
• The rope, cable, anchor, body harness
and all connectors need the tensile strength
to withstand twice the potential impact
energy of a 6-foot fall, or of the free-fall distance — but in all cases minimum breaking
strength must be at least 5,000 pounds ( 2,268
kg). Connectors and anchors should be made
of drop-forged, pressed or formed steel or an
equivalent material.
• Rescue a fallen employee immediately,
or assure that the fallen employee can self-rescue.
• Inspect each system for wear and damage before each use. After a fall, the arrest
system must be removed from service for
inspection.
• Do not attach arrest systems to guardrails
or hoists. In general, the arresting anchor
should be independent of any scaffold, ladder
or supporting structure that might itself fail.
• Rig lines to avoid abrasion or cutting
over rough surfaces and edges.
• When used at hoist
areas, rig each arrest system to allow worker
movement only as far as
the working surface.
OSHA regulations
don’t mention it specifically, but it’s good practice to select a body harness system with the
lifeline connection in
front of the chest or belt
(the harness system in
the photo is a good
example). Some harness-es are designed to connect at the back — above
the shoulder blades, for
instance. This may be
convenient for working, because the lifeline trails behind, but a worker dangling
from a rope this way is helpless and can’t
assist in the rescue. If the rope and connection are in front, the worker can reach it to
attach an additional haul rope or to swing
over to a point of evacuation.
A thorough presentation on ladder safety is available at the Oregon OSHA website
( oreseia.org/solar_safety_training.htm).
Also, for information regarding personal
fall arrest systems visit the OSHA web site:
SOLAR ENERGY INTERNATIONAL
An instructor at Solar Energy International shows the proper use
of the safety harness, anchored at the roof ridge.
osha.gov/SLTC/etools/construction/
falls.html. ●
C.By ron Winn, Ph.D. (byron@engr.
colostate.edu) is chair of the Solar Rating and
Certification Corp. (which certifies solar water-heating collectors and systems) and professor
emeritus of mechanical engineering at Colorado
State University. “Safety Matters” is authored
on a rotating basis by Winn and John Wiles, a
leading expert on the photovoltaic system requirements of the National Electrical Code.
TM
