Trenches and Earthworks: OSH Rules & Documents
A foundation trench, two metres deep, vertical walls with no support at all. A worker climbs down to fix the formwork, and at that moment the wall slides in.
A foundation trench, two metres deep, vertical walls with no support at all. A worker climbs down to fix the formwork, and at that moment the wall slides in. Being buried in a trench is one of the most common fatal causes of accidents in earthworks - and it can almost always be prevented. Several hundred kilograms of earth fall on a person in a fraction of a second. In this article I go through it step by step: at what depth a trench must be secured, how to get in and out, where to check underground services and what documents to keep. If you would rather not write the risk assessment and IBWR (safe work procedure) for trenches from scratch, BudoReady gives you ready-made earthworks documentation templates to fill in with your company's data.
Key points in brief
- Trenches with vertical walls and no shoring are permitted only to a small depth - deeper ones require shoring, strutting or battering (sloping).
- The basis is the Regulation of the Minister of Infrastructure of 6 February 2003 (the section on earthworks).
- Before digging, you check the underground services - gas, electricity, water, sewerage, telecoms.
- Earthworks in deeper trenches are often particularly hazardous work - they require an IBWR and supervision.
- The full set: risk assessment, IBWR, BIOZ plan (health and safety plan, where required), service clearances, instructions and training.
Why a trench kills more often than it seems
A trench looks harmless - it is "just a hole in the ground". But earth is heavy. A cubic metre of soil weighs over a tonne. When a trench wall slides in, a person at the bottom has no chance to escape, and even partial burial of the chest can be fatal. Add to that the less obvious hazards: damaging a gas installation, electrocution from a cable, flooding with water, falling into the trench from above.
Safety rules for earthworks are governed by the Regulation of the Minister of Infrastructure of 6 February 2003 on occupational health and safety during construction work - the same instrument that governs scaffolding and working at height. The chapter on earthworks is specific about protective measures.
When trench walls must be secured
This is the crux. Not every trench requires shoring, but the threshold is set low and depends on the soil. The general rule: trench walls must be secured against collapse, unless the trench is shallow and dug in stable ground at a safe slope.
| Situation | Protection |
|---|---|
| Shallow trench in stable ground | A safe slope of the sides may be enough |
| Vertical-walled trench deeper than safe | Shoring (casing) or strutting the walls |
| Trench in waterlogged / unstable ground | Casing, dewatering, particular care |
| Trench next to existing buildings / roads | Protection and supervision, clearances, a design |
In practice: a vertical-walled trench above roughly 1 m in most soils requires securing - shoring or strutting. In less stable ground the threshold is even lower. An alternative method is battering - giving the walls a safe slope so that the ground holds itself. What is safe depends on the type of soil, the water level and any loads near the edge. For deeper and more difficult trenches a shoring design is sometimes needed.
Underground services - check before you sink the bucket
Before the excavator starts, you have to know what is underground. Damaging an installation is not just a repair cost - it is a real danger to life and a serious matter for the inspector.
- Check the underground services maps - gas, electricity, water, sewerage, telecoms, district heating.
- Obtain clearances and conditions from the utility operators wherever the trench runs near an installation.
- In uncertain zones, dig by hand - near existing installations you use hand tools carefully instead of an excavator.
- Assign supervision - work near live networks often requires supervision by the utility operator or an authorised person.
Cutting a power cable with an excavator bucket or rupturing a gas main is a scenario that begins with "there was nothing here by the looks of it". The map and the clearance are your insurance.
Getting in, getting out and working in the trench
A secured trench alone is not everything - how people move around in it matters too.
- Safe access and egress - ladders, ramps. A person does not clamber up the shoring or jump into the trench.
- Distance of spoil from the edge - the excavated earth is placed a safe distance from the edge, so as not to overload the wall or let it fall back in.
- No standing under a working excavator - no one is within reach of the bucket.
- Securing the edge - barriers or markings so no one falls into the trench from above; lighting and marking after dark.
- Crossings over the trench - footbridges with barriers where people have to cross.
Working in a deeper trench is often particularly hazardous work within the meaning of the regulations - which means additional requirements: direct supervision, an instruction briefing before starting, and safeguards. This is where the IBWR comes in.
IBWR for trenches - when and why
The IBWR (Safe Work Execution Procedure) is a document describing, step by step, how to carry out a specific job safely. For earthworks, especially deeper trenches and work near installations, the IBWR sets out the order of work, how the walls are secured, access, supervision, and conduct in the event of a hazard.
It is the document that most often causes trouble, because it has to be written for the specific task, not "in general". We set out when the IBWR is mandatory and what it must contain in the article IBWR - when it is mandatory. Trenches are one of the classic cases where the inspector asks for the IBWR.
The documents you must have
The full set for trenches and earthworks:
- Occupational risk assessment covering the risk of wall collapse, falling into the trench and damaging installations.
- IBWR for earthworks - for deeper trenches and hazardous work.
- BIOZ plan - where required by the Construction Law.
- Clearances and underground services maps, utility operators' conditions.
- Trench shoring design - for deep or difficult trenches.
- OSH instructions and training cards - a briefing before hazardous work.
From 8 July 2026, the PIP reform (Polish Labour Inspectorate) gives inspectors stronger tools, and an unsecured trench is grounds for stopping the work and a fine of up to 5,000 zł. Details are in the article PIP reform 2026 - what is changing.
Frequently asked questions
At what depth do I have to shore a trench?
It depends on the soil, but in most cases a vertical-walled trench deeper than about 1 m requires securing - shoring or strutting. In unstable or waterlogged ground the threshold is even lower. An alternative is battering, that is giving the walls a safe slope. For deep trenches a shoring design is sometimes needed.
Do I have to check underground services before every trench?
Yes. Before starting earthworks, the routes of underground installations - gas, electricity, water, sewerage, telecoms - are established from services maps and clearances with the utility operators. Near live installations you dig by hand and under supervision. Damaging a network is a danger to life and a serious breach.
Is working in a trench particularly hazardous work?
Work in deeper trenches and near installations often qualifies as particularly hazardous work. This means additional requirements: direct supervision, an instruction briefing before starting the work, and particular safeguards. In such cases an IBWR is drawn up for the specific task.
What are the penalties for a trench without secured walls?
A PIP inspector can stop the work and issue a fine - from 8 July 2026 up to 5,000 zł, and up to 10,000 zł for a repeat offence. If a worker is buried, the employer faces criminal liability. An unsecured trench is one of the most common sources of fatal accidents in earthworks.
Ready-made earthworks documentation - the FULL package
A risk assessment for trenches, an IBWR for earthworks, instructions - you can write it yourself in the evenings or take the ready-made templates and enter the site data.
For earthworks the best choice is the FULL package (749 zł, 45 files) - the only one with a full set of IBWR for 6 types of work, including earthworks and trenches. It contains the risk assessment, OSH instructions and training templates, in Polish and Ukrainian. For a smaller scope there is STANDARD (449 zł, 27 files) and STARTER (299 zł, 10 files), but the IBWR for trenches is only in FULL.
The promotion runs until 7 July 2026 - just before the PIP reform. See BudoReady packages and choose FULL: put the documentation together once and have peace of mind before the excavator starts.
This article is for information only and does not replace advice from an OSH (occupational safety and health) specialist or the current legal position. Document templates require individual adaptation to the reality of your company and specific workstations, and the current legal position should be verified as at the date of use.