Rain, a Six-Foot Trench, and a Concrete Deadline
At a utility project, a crew is installing a 6-foot-deep sanitary lateral in a 22-foot-long excavation. The competent person inspected it at 7 a.m. and classified the soil as Type B; a trench box is on site but is being used 300 feet away on another excavation. At 1 p.m., after a light rain, the foreman tells the crew to hand-grade the last 8 feet of trench bottom so pipe can be laid before the concrete supplier's 4 p.m. cutoff. The box would take about 45 minutes to move and set. A journeyman says the walls look 'a little raveled' near the north end but that he has worked in worse. The crew has three laborers and one operator; two workers are ready to enter. The general contractor's safety manager is not on site.
1. What must the crew lead do before anyone enters the excavation? Identify the conditions that changed since the morning inspection and explain the authority to stop work.
Read the worked answer
Stop entry. The lead should keep all workers out and treat the excavation as unverified until the competent person re-inspects it. The morning inspection no longer governs: the soil was classified Type B, the trench is 6 feet deep, and light rain has fallen since 7 a.m. Rain changes pore pressure and can cause raveling, and the journeyman's observation of 'raveled' walls is a warning sign, not a minor comment.
At 6 feet, a protective system is required, and the trench box on site is the planned system. The box is 300 feet away and would take about 45 minutes to move and set-far less time than a rescue or a re-excavation. The lead's stop-work authority is not a suggestion; it is the mechanism that prevents a fatality when schedule pressure overrides a changed condition.
First actions: clear the area, barricade or cover access, call the competent person, and notify the foreman in writing that entry is suspended pending re-inspection and box placement.
2. The foreman argues that moving the box will miss the 4 p.m. concrete cutoff. How should the lead evaluate and communicate that trade-off?
Read the worked answer
Frame the trade-off correctly. The choice is not '45 minutes versus concrete cutoff'; it is '45 minutes versus an unprotected 6-foot excavation in rain.' Concrete can be rescheduled or placed later; a collapse is not recoverable. The lead should not accept the foreman's deadline as a reason to skip the protective system.
Practical response: call the concrete supplier and ask for the last available delivery or the next-day slot, notify the GC of the changed condition, and redirect the crew to work outside the excavation while the box is moved. The 45-minute estimate should be verified with the operator and the competent person, because setting the box may require excavation adjustment.
Communication: state the requirement, not a personal opinion-'the competent person must re-inspect after rain, and the box must be set before entry.' Give the foreman a revised sequence and time, so he has a schedule answer rather than only a refusal.
3. What should be documented, and who should be notified, whether or not an incident occurs?
Read the worked answer
Document the changed condition and the stop-work decision in the daily log: time of rain, the journeyman's report, the lead's order, the competent person's re-inspection, and when the box was set. Photograph the north end and the excavation before and after protection. This record matters for safety, for any delay claim, and for the next shift.
Notify: the competent person immediately, the general contractor's safety representative, and the lead's superintendent. If the foreman directed entry, the notification should be factual, not accusatory: 'entry was suspended at 1:10 p.m. pending re-inspection after rain.'
Protect the journeyman who spoke up. He identified a hazard; he should not be treated as the cause of the delay. A short crew discussion-not a debate-should reinforce that anyone can stop work for an unsafe trench. If the foreman repeats the instruction, the lead should escalate to the safety manager and document the repetition.