Supported Scaffold Safety

1. Supported Scaffold
Safety
WAC 296-874

2. Objectives
Familiarize yourself with:
• Duties of a “Competent person”
• Basic scaffold requirements
NOTE: Links to the rule (WAC 296-874) and other
resources are on a slide at the end of this presentation

3. Some Supported Scaffolds
Supported scaffolds are scaffolds that are have an attachment to the ground
rather than are suspended by cables.

4. What is a “Competent Person”?
A competent person is able to:
• identify existing and
predictable hazards
• identify working conditions
that are unsanitary, hazardous
or dangerous and
• has authority to eliminate hazards
NOTE: This training does not make a person a “competent person” as
defined by the rule.

5. Erecting and Dismantling
• A competent person
determines feasibility of fall
protection.
• Employer must provide maximum
feasible fall protection.
Questions to ask are:
• Is there a nearby structure from which a lifeline can be dropped that the worker can tie
off to?
• Can we install guardrails immediately after installing the fabricated frames and before
moving to the next level?
• Can we sequence disassembly to keep the worker protected for the maximum feasible
time?
• Whatever is feasible to do must be done during the assembly/ disassembly stages

6. Inspection by a competent person
▪ Must occur at the beginning of each
shift.
▪ After any occurrence which could affect a
scaffold's structural integrity, such as:
▪ adverse weather
▪ removal of parts
▪ damaged parts

7. If you don’t have inspections done…
You might go to a jobsite
some day and find this!!

8. What do I have to do?
Damaged or weakened parts must
immediately be:
• repaired, replaced, braced to meet
minimum strength or
• removed from service until repaired.

9. Or bad things can happen…
The safety of a scaffold is highly dependent upon
being built right in the first place. You should have
regular inspections to make sure a problem hasn’t
developed over time.
When scaffolds fail, they fail in a catastrophic way
and can cause many serious injuries or deaths
depending on who is on or around it when it fails.

10. Worker must be trained on:
• Recognizing hazards of the type of scaffold they’ll be using
• Understanding the procedures to control or minimize hazards
• Hazards including: electrical, falling off the scaffold, and falling
objects
• How to erect, maintain and disassemble the fall protection and
falling object protection systems
• Using the scaffold and handling materials on the scaffold
• Maximum intended load and capacity
• Other information as needed
Employees need training so they don’t misuse the scaffold or do things that will cause it
to lose its integrity, such as removing cross bracing so they can do their work. Training
needs to be specific to the scaffold the workers will be using. Job-specific issues would
include power line clearances, surface conditions.

11. Worker must be retrained when:
• You believe an employee lacks the skill or
understanding to safety erect, use or
dismantle a scaffold,
• If an employee's work is inadequate,
• If there is a change in any of the following
that presents new hazards:
• Worksite
• Type of scaffold
• Fall protection
• Falling object protection
• Other equipment

12. Provide fall protection for …
• employees on a scaffold more than 10 feet
above a lower level by one of these
methods:
• guardrails, which must be:
•Installed along open sides and ends and
•In place before employees use the scaffold
OR
• personal fall arrest system
•In accordance with WAC 296-155 Part C-1
•Must be attached to the structure or
a lifeline -- not the scaffold

13. Requirements for Guardrails
• Guardrails consist of toprail, midrail and falling
object protection, such as a toeboard
• The toprail must be between 38” – 45” high
and withstand a 200 lb. force
• The midrail must be installed at a height
approximately midway between the top edge
and the platform surface and withstand a 150
lb. force
• A toeboard, when used, must be 3 ½ inches
tall and able to withstand a 50 lb. force

14. Guardrails
“X” brace can substitute for top rail or mid rail but
not both.
Cross bracing is acceptable in place of a midrail when the crossing point of two braces is
between 20 inches and 30 inches above the work platform.
Cross bracing can be used as a top rail when the crossing point is between 38 inches and 48
inches above the work platform.
The end points at each upright must be no more than 48 inches apart.

15. Examples of lack of fall protection

16. Provide a ladder, ramp or direct access
For platforms more than 2 feet above
or below a point of access
In the picture on right, the worker is climbing the
scaffold frame, which is in violation of the rule.

17. Power line clearance
Insulated lines All other power lines
50 – 299 volts = 3 feet 50 – 50k Volts = 10 feet
Over 50k Volts, add .4” per KV
Examples of scaffolds too close to power lines

18. Footings
•Support the load without settling or displacement
• Sound • Rigid
• Level

19. Unstable Footing Examples

20. Platform specifications
Each working level fully planked; no more than
1” gaps
Minimum platform and walkway width of 18”
Extend end over support 6” min (Maximum end
extension 12”)
Overlap planks between scaffold sections by at
least 12”
Front edge within 14” of the work
Don’t paint planks since they will hide defects

21. Scaffold platforms must
be fully planked…
(and this employee
needs fall protection)
Example of improper scaffold planking

22. Plank cannot extend more than 18”
beyond its support

23. Platforms
• Scaffold grade or equivalent
• 1,500 lb-f/in2 (stress grade)
construction lumber
• Manufactured planks used according to
manufacturer’s recommendations

24. Wood Plank Inspection
Damaged wood planks include:
Rot, "squishy" feel, or powdery appearance from termite damage
Cupping of 3/8" or more on a 10" wide or 1/2" or more on 12" wide plank.
Crook of more than 5/16”, bow of more than 7/16” or twist of more than ¾” on a
10’ long 10” board.
Wane of more than ¼ the width and ¼ the thickness for more than ¼ the length
of the plank.
A split that has a length of 1 ½ times the board width or more.
Knots that are more than 1 ½” diameter if loose or 2” diameter if tight on a 10”
plank.
A notch cut into a plank more than 1/3 the plank width.
Any saw kerf cut across the plank weakens the plank by the depth of the cut.
The problem may not be noticed if the plank is later laid with the cut side down.

25. Capacity
• 4 times the intended load + scaffold weight
• Planks must not deflect more than 1/60 of
span when loaded
Downward deflection must be no more than 1.8”
10’ total plank length
6” overlap
6” overlap

26. Example of Overloaded scaffold

27. Overlaps
• Angled plank is not on the bottom
• Not fully planked at transition
• No guardrail at transition
On a corner, planks that don’t come in at a right angle to the support must be
on the bottom and then overlapped by the planks that are at a right angle.

28. Example of Unstable Support
• Forklifts and
front-end loaders
not designed by
the manufacturer
for such use.

29. Guying, Tying or Bracing
•If the ratio of height to base is more than 4:1
Install guys every 26’ above this tie point for scaffolds more than 3’ wide.
Install these guys at each end of the scaffold and space additional middle guys
no more than 30’ apart.
If you use a cantilevered work platform (outside the framework of the scaffold),
then you must use some type of bracing such as tying or outriggers to prevent
the scaffold from tipping.

30. Other scaffold use rules
• Don’t
• move a scaffold when
someone is on it.
• work on a scaffold covered
with snow or ice.
• work on a scaffold during a
storm or high winds.
• use boxes, barrels or a
ladder on top of a scaffold to
increase its height.
• Do clean up debris on
platforms before it
accumulates.

31. Unacceptable Scaffold Example
• Shore or “lean to”
• Also, a competent person
must approve the use of
dissimilar metals
• Intermixed scaffold
components must fit together
without force and not effect
the structural integrity of the
scaffold.
This is an example of a lean-to scaffold. In this
picture, the workers have a shore scaffold on top of
another shore scaffold. Access is unsafe both from
above and below. The only thing holding this scaffold
up is the DUMPSTER!

32. Some resources for you
• For all the rules related to scaffolds, read WAC 296-
874, Scaffolds
• For general safety information, visit our website at
www.LNI.wa.gov/safety
• For more training tools, visit our Training website at:
www.LNI.wa.gov/Safety/TrainTools/default.asp
• For additional assistance, you can call one of our
consultants. Click below for local L&I office
locations:
www.LNI.wa.gov/wisha/consultation/regional_consul
tants.htm

33. Thank you for taking the
time interest to learn
about safety and health
and how to prevent
injuries and illnesses.