Common site safety failures, and how to design them out
Spring & Co, Stockport. Construction & property consultants since 1992
Most serious site safety failures trace back to a decision made months before anyone broke ground, by someone who never had to build the thing. A hazard that gets removed on a drawing costs a design review. The same hazard, left in until site, costs a permit-to-work, a guardrail and a nervous banksman, and at the far end it costs an inquest. Closing that gap is the whole job of a principal designer.
That is the uncomfortable part.
Where do most site safety failures start?
Look at the Health and Safety Executive's numbers and the pattern barely moves from one year to the next. Close to half of the workers killed on British construction sites die in a fall from height, HSE's figures show, and a large share of the rest are struck by moving plant or caught in a collapse. Now look at when those hazards actually entered the project. The fragile rooflight that nobody could stand near safely was specified at Stage 4. The plant room with no safe way in was drawn that way. The deep drainage run tight against an existing wall was set out before anyone priced the temporary works. By the time a site manager sits down to write a method statement, the risk is already set in the concrete.
Schedule 3 of the Construction (Design and Management) Regulations 2015 lays out the General Principles of Prevention, and the order is not a suggestion. Avoid the risk first. Only when you genuinely cannot remove it do you control it, and PPE comes last of all. Most of the industry reads that list backwards.
The failures we see over and over
After thirty years of monitoring builds across the North West, the same handful of failures come round again, and almost every one was decided at a desk. Here is what they look like and where they were really made.
| Failure on site | Where it was actually decided | How you design it out |
|---|---|---|
| Fall through a fragile roof | A rooflight or liner panel specified with no thought given to future maintenance access | Specify non-fragile assemblies to ACR guidance and draw permanent anchor points and safe access onto the roof plan |
| Worker struck by a craned load | A layout with no laydown area, so materials get lifted over live work | Set crane arcs and exclusion zones at design stage and give the site a real logistics plan, not an afterthought |
| Collapse of a deep excavation | A dig set out tight to an existing foundation with no allowance for temporary works | Move the run, design the support, or sequence the works so the two never happen at once |
| Asbestos or silica exposure | A refurbishment scope that assumes the building matches its old drawings | Commission an intrusive survey before the design freezes, not after the breaker is already running |
| Vehicle striking a pedestrian | One gate serving both plant and people because the boundary was only ever drawn once | Separate vehicle and pedestrian routes on the site plan from the first sketch |
What does it mean to design a risk out under CDM 2015?
The Construction (Design and Management) Regulations 2015 came into force on 6 April 2015, and they put a legal duty on the people who design a building, not only on the people who build it. Regulation 9 uses the word eliminate. Where a foreseeable risk to anyone building, using or maintaining the structure can be removed so far as is reasonably practicable, removing it is the expectation, and controlling it is only the fallback.
The word doing the heavy lifting there is maintaining. A building is on site for eighteen months and then stands for fifty years, and someone has to clean the high-level glazing, service the rooftop plant and swap out a failed panel every one of those years. If the drawing cannot show us how that person does the work without a rope and a prayer, the design has quietly created a future fall and handed it to a stranger. A good clerk of works checking the build against the drawings will catch a lot on site, but the cheapest fix is always the one made before the drawing is issued.
Scale brings a hard trigger too. Under Regulation 6, a project is notifiable to HSE on form F10 if the work is planned to last longer than 30 working days with more than 20 people on site at once, or to run beyond 500 person-days. Notifiable or not, the designer duties still bite. A two-week shopfit gets the same hierarchy of control as a hospital wing. If you are early on a scheme and want a second pair of eyes on how buildable and how safe the design really is, that is exactly what our CDM principal designer service is for.
Why more paperwork will not fix this
Here is where we lose friends. The industry's reflex, whenever something goes wrong, is to reach for more paper. A longer method statement. Another risk assessment. A fresh round of toolbox talks. It feels like doing something, and it is usually the least effective thing on the table, because a method statement is a written description of a risk you have decided to keep. The Work at Height Regulations 2005 told you to avoid the work at height in the first place. A RAMS folder two inches thick is often the paper trail of a hazard that could have been drawn out and never was.
There is a price on getting this wrong that goes well beyond the human one. HSE recovers its investigation costs through Fee for Intervention, charged at more than £160 an hour from the moment an inspector finds a material breach, and a RIDDOR-reportable fall drags in an insurance claim and a formal investigation on top. None of that shows up in the tender.
The honest trade is this. Designing a risk out usually costs a little more at the drawing stage, and the client feels that in the fee long before they ever feel the benefit of an incident that did not happen. We have lost work to firms who will nod a design through and let the site sort it out later. We think that is a poor bargain and we say so, and now and then it costs us the job. We would rather lose a tender than sign a drawing we would not want read out in a courtroom. Tight project management from the start makes that argument far easier to win, because safety and programme stop pulling in opposite directions.
What does this look like on a Stockport site?
Round here it is rarely a clean green field. Most of the work across Stockport and the wider Greater Manchester belt lands on brownfield: former mills and old industrial yards, on cramped town-centre plots like the ones around Chestergate and the Town Centre West regeneration. Two things follow. Anything built before 2000 has to be treated as containing asbestos until a survey proves otherwise, so the survey has to lead the design rather than chase it. And these plots sit hard against live roads like the A6, which makes keeping plant away from the public a design problem long before it is a banksman's problem. A traffic plan that works on a two-acre field falls apart on a quarter-acre site wedged between a railway line and a bus route.
Common questions
Whose job is it to design out site safety risks?
Under CDM 2015 the principal designer leads on managing health and safety through the pre-construction phase, and every designer on the project shares the duty. The client appoints the principal designer in writing. It is a legal role with named duties, not a courtesy title handed to the lead architect.
Does designing out risk cost more?
A little more at the design stage, and usually less over the whole job. Removing a hazard on a drawing is cheaper than guarding it for eighteen months on site, and far cheaper than an HSE investigation, a stopped programme or a personal injury claim. The saving just lands in a different budget line.
You cannot inspect safety into a bad design. You can only draw it in from the start. If you are planning a build in the North West and want the risks taken out on paper before they ever reach the site, talk to our health and safety team or call us on 0161 476 4456. We would far rather have the awkward conversation at Stage 3 than the formal one after.