High-risk work I: working at heights

Falls are the leading cause of serious injury and death in construction. The Bureau of Labor Statistics counted 1,034 construction deaths in 2024, released in February 2026, and 389 of them, about 38 percent, were falls, slips and trips. Falls are the first of OSHA's construction Focus Four hazards, with struck-by, caught-in or between, and electrocution, and fall protection in construction has been OSHA's most frequently cited standard for many years. On Larkspur Commons, with a two-story podium and four stories of wood frame going up at the rate of a floor every few weeks, falls are the top hazard for most of the project, and this lesson treats them in detail.

HSE-212, Working at Heights and Fall Protection, in the Safety stream, covers fall protection equipment and techniques for workers. This lesson is about what a supervisor plans, provides and checks.

When fall protection is required

OSHA's construction fall protection standard, Subpart M, requires fall protection where an employee on a walking or working surface with an unprotected side or edge is 6 ft or more above a lower level. Other subparts set their own triggers: 10 ft for scaffolds under Subpart L, and ladder rules under Subpart X. A written fall protection plan is permitted only for leading-edge work, precast concrete erection and residential construction where the employer can show that conventional fall protection is infeasible or creates a greater hazard, and the plan must be prepared by a qualified person. On Larkspur Commons, Thornbury uses conventional fall protection on every floor and prepares a written site plan anyway, because the plan forces the planning.

The fall protection hierarchy

The hierarchy of controls from lesson 5 applies to falls in a specific form. Each step down depends more on equipment working perfectly and on people using it correctly every time.

The difference between restraint and arrest matters a great deal. A worker in restraint cannot fall; a worker in fall arrest does fall, and depends on the anchor, lanyard and harness to stop them before they hit something, and then on a rescue. Wherever a restraint system can be used, it is better.

Planning fall protection for a floor

On Larkspur Commons, the fall protection plan for each wood-frame floor is a two-page document prepared by Ridgeline Framing's foreman with Omar before the floor starts. It covers the hazards and how each is protected, the anchors and their locations, the equipment, the procedures for installing and removing guardrails, the rescue plan, and the names of the workers trained in it.

Anchors are the part most often improvised. A worker who needs to tie off and cannot see an anchor will find something: a top plate, a pipe, a joist hanger. Those may not hold the forces of a fall. Thornbury's floor plans show the engineered anchors that will be installed for that floor, roof truss anchors and floor-plate anchors rated for fall arrest, and the framing sequence includes installing them before workers need them. A fall arrest anchor must be able to resist the forces of a fall with a safety margin; in practice that means using anchors certified for the purpose and installed as their instructions require, or anchors designed by an engineer, rather than judging strength by eye.

Fall clearance

A fall arrest system only works if it stops the worker before they hit the floor below or an obstruction. The total distance needed, the fall clearance, adds up several components. Supervisors should check it whenever workers tie off to an anchor at or below foot level, which is common on a wood-frame deck.

# Fall clearance check for a 6 ft energy-absorbing lanyard on a floor-level anchor (illustrative values)
lanyard = 6.0                 # lanyard length, ft
anchor_below_dring = 5.0      # anchor at floor level, D-ring about 5 ft above the floor
free_fall = lanyard + anchor_below_dring
deceleration = 3.5            # maximum deployment of the energy absorber (manufacturer data)
harness_stretch = 1.0
dring_to_feet = 5.0
safety_margin = 3.0
required = free_fall + deceleration + harness_stretch + dring_to_feet + safety_margin
for name, available in [("floor to floor, levels 4-5", 10.0), ("deck to grade at the podium", 23.5)]:
    ok = "OK" if available >= required else "NOT ENOUGH - use a self-retracting lifeline or restraint"
    print(f"{name:28s} available {available:.1f} ft, required {required:.1f} ft -> {ok}")
print(f"free fall {free_fall:.0f} ft exceeds 6 ft: {free_fall > 6}")

floor to floor, levels 4-5   available 10.0 ft, required 23.5 ft -> NOT ENOUGH - use a self-retracting lifeline or restraint
deck to grade at the podium  available 23.5 ft, required 23.5 ft -> OK
free fall 11 ft exceeds 6 ft: True

With the anchor at the worker's feet, a standard lanyard needs more clearance than one story of a wood-frame building provides, and the free fall also exceeds the 6 ft limit in OSHA's personal fall arrest rules. That is why the Larkspur Commons plan specifies self-retracting lifelines on overhead or horizontal anchors for leading-edge work above a finished floor, and restraint wherever the work allows. The figures in the example are illustrative; real calculations use the equipment manufacturer's data.

Guardrails, openings and the trades that remove them

Guardrails are the most effective fall protection on most sites, and the most often removed. Every trade has a reason: landing materials, installing windows, setting equipment, running pipe. The problem is not removal but what happens after. Thornbury's rules are that only the trade that needs the opening may remove a guardrail section; it must protect the opening while it is open, by tying off its own workers and barricading the area for others; it must replace the guardrail before it leaves the area, even for a break; and it must tell the superintendent. Lesson 7 described how material landing platforms with swing gates removed most of the reasons for taking guardrails down on Larkspur Commons. Lesson 8 showed what happens when an opening cover is lifted and not replaced.

OSHA requires guardrail top rails to be 42 in, plus or minus 3 in, above the walking surface, able to withstand a 200 lb force applied outward or downward, with midrails or equivalent and toe boards where objects could fall. Purpose-made guardrail systems clamp to slab edges or attach to wood-frame floors and are quicker to install and inspect than site-built rails.

Ladders and scaffolds

Ladders cause a large share of falls from lower heights, including many serious injuries. Thornbury's site rules limit their use: stair towers are installed early so that workers do not climb between floors on ladders, and platform ladders or rolling podiums replace step ladders for interior work wherever possible. Where ladders are used, they must be in good condition, set at about four to one, secured, and extended about 3 ft above the landing, and workers keep three points of contact and do not carry loads in their hands while climbing.

Subpart L requires scaffolds to be designed by a qualified person, erected, moved, altered and dismantled under the supervision of a competent person, inspected by a competent person before each shift and after any occurrence that could affect their integrity, and used only within their rated loads. The tag system on Larkspur Commons is simple: green means inspected and safe to use, red means do not use, and a scaffold with no tag is treated as red. Workers who alter a scaffold, even to move a single plank, have made it a red scaffold until it is re-inspected.

Aerial work platforms

Boom lifts and scissor lifts are used for exterior cladding, high ceilings in the commercial units and the parkade services. Operators must be trained and familiarized on the model. In boom lifts, occupants wear a harness with a short lanyard attached to the platform's anchor point, so that a sudden movement does not throw them out; in scissor lifts, the guardrails are the primary protection, and the manufacturer's instructions govern whether tie-off is required. Lifts are not used as material hoists, guardrails are never climbed, and the ground is checked for soft fill, slopes and overhead lines before setup.

What a supervisor checks every day

• Every open edge, opening and stair has a guardrail or secured cover, or workers at it are tied off under the plan.
• Anchors for today's work are installed and identified before workers need them.
• Harnesses and lanyards are inspected before use, and damaged equipment is removed from service.
• Self-retracting lifelines are used where clearance is short.
• Scaffold tags are green and current; no one is on a red or untagged scaffold.
• Ladders are the right type, secured and used correctly, and stairs are used where they exist.
• The rescue kit and trained rescuers are on site and know where today's work is.

A supervisor's check before work at height starts

Plans and equipment matter only if they are in place when the work begins. Before a crew starts work at an open edge, the supervisor or foreman should be able to answer a few questions without looking anything up. Which level of the fall protection hierarchy is being used, and why not a higher one? If workers will be tied off, where are the anchors, who confirmed that they are rated for the load, and is the fall clearance enough for the connector being used? Has every worker on the crew been trained on this equipment and inspected their own harness today? Who will carry out a rescue if someone falls, with what equipment, and how quickly can it be done?

Ben Kowalski runs this check as part of his morning field-level hazard assessment with the Thornbury carpenters, and Ridgeline's foreman does the same with the framing crew. When an answer is missing, the work waits until it is found. The check takes a few minutes and has stopped work twice on Larkspur Commons: once when a new crew arrived with lanyards instead of the self-retracting lifelines the plan required above a finished floor, and once when the rescue kit had been moved to another level.