The hazards and the atmosphere — Confined Spaces Practice

Sample questions

1. 01You are listing what could make a cable chamber dangerous before a job. Which three sources of danger does L101 lead you to think about?

   • AThe weather, the time of day and the team size
   • BLive cables, trip hazards and nearby plant noise
   • CIts depth, its width and how many ways in it has
   • DWhat is in it, what the work adds, what gets in

   Why: HSE guidance in L101 says hazards can already be in a space or be brought into one that would otherwise be safe, and the ACOP asks the risk assessment to cover the condition and previous contents of the space, hazards from the work and hazards from outside. Size and the number of openings are not the test of danger, and electricity, trips and noise are other hazards covered by other law.

2. 02In a basement plant pit, which of these hazards is one the Confined Spaces Regulations deal with, rather than other law?

   • AElectric shock from an exposed busbar
   • BPart of the pit wall starting to collapse
   • CLoss of consciousness caused by fume
   • DNoise from a compressor running nearby

   Why: Loss of consciousness or asphyxiation from gas, fume, vapour or lack of oxygen is a specified risk under regulation 1(2). HSE guidance in L101 says electricity, noise and collapse are other hazards that the Regulations do not deal with; the Electricity at Work Regulations 1989 cover shock, and other law covers noise and collapse.

3. 03A storm water drain chamber has been sealed for months with no work done in it. The site says nothing could have got in, so the air must be fine. What should you think?

   • AGas only builds up if the cover was left open
   • BSealed means safe, as nothing new could get inside
   • CIt only matters if the chamber once stored fuel
   • DBiological processes inside can produce toxic gas

   Why: HSE guidance in L101 lists biological processes in sewers, storm water drains, wells and storage tanks as a natural source of toxic gas, with no work going on at all. Keeping the chamber sealed lets that gas build up rather than clear, so a sealed chamber is a reason for more care, not less.