Guardrail dimensions and forces
A top rail at 42 inches plus or minus 3 inches, withstanding 200 pounds of downward force. A midrail withstanding 150 pounds. A toeboard of at least 3.5 inches. All at 29 CFR 1926.502(b).
A short list of numbers that appear together and get swapped in exam options because they belong to the same rule.
The numbers
| Component | Requirement | Provision |
|---|---|---|
| Top rail height | 42 inches, plus or minus 3 | 1926.502(b)(1) |
| Top rail strength | 200 pounds downward force | 1926.502(b)(3) |
| Midrail strength | 150 pounds | 1926.502(b)(5) |
| Toeboard height | 3.5 inches minimum | 1926.502(j)(3) |
Two hundred for the top rail, one hundred and fifty for the midrail. The top rail carries more because it is the one a falling worker meets.
A top rail may be between 39 and 45 inches. A question giving you 40 inches and asking whether it complies is testing whether you know the tolerance exists, and the answer is yes.
What the toeboard is for
Stopping material rolling off an edge onto somebody below. It is a falling-object rule rather than a fall-protection one, which is why it has its own provision.
When a guardrail is the answer
Guardrails are one of three conventional systems, alongside safety net systems and personal fall arrest systems.
Questions sometimes ask which is appropriate. A guardrail protects everybody passively and needs no training or inspection by the worker, which is why it is generally preferred where it is practicable.
Where to find it
Subpart M, at 1926.502. Tab it. This is one of the most commonly needed lookups in the whole paper.
Common questions
How high must a guardrail top rail be?
42 inches, plus or minus 3 inches, so between 39 and 45.
What force must the top rail withstand?
200 pounds of downward force. A midrail must withstand 150.
What is the minimum toeboard height?
3.5 inches.
What is a toeboard for?
Stopping material rolling off an edge onto somebody below. It is a falling-object protection.
What are the three conventional fall protection systems?
Guardrail systems, safety net systems and personal fall arrest systems.