Guardrail systems must be capable of withstanding certain forces to ensure they protect workers from falls. Here's a breakdown of the load rating requirements:

• Top Rails: Must withstand a force of at least 200 pounds (890 N) applied within 2 inches of the top edge in any outward or downward direction 1, 2, 8. For guardrail systems installed on single-point or two-point adjustable suspension scaffolds, the top rail must withstand at least 100 pounds (445 N) 3, 4.
• Midrails: Must withstand a force of at least 150 pounds (666 N) applied in any downward or outward direction 2, 8, 11. For guardrail systems with a minimum 100-pound toprail capacity, the midrail must withstand at least 75 pounds (333 N) 3, 4.
• Deflection: When a 200-pound load is applied downward, the top edge of the guardrail must not deflect to a height less than 39 inches (1.0 m) above the walking/working level 1, 2, 8.

It's important to ensure that guardrail systems are constructed and maintained to meet these load requirements to provide adequate fall protection [1].