Working Near District Heating Pipes

District heating pipes carry hot water at temperatures up to 120°C and pressures up to 25 bar.
Striking a live district heating pipe during excavation causes an immediate scalding hazard.
Pre-insulated district heating pipes can be difficult to distinguish from other buried services.
Service plans, CAT and Genny surveys, and trial holes must be used to locate pipes before digging.
The outer casing of pre-insulated pipes contains a leak detection wire that can give false CAT signals.
Hot water escaping from a damaged pipe can fill an excavation rapidly, scalding workers inside.
Mechanical excavation within the safe zone of a district heating pipe must be prohibited.
Emergency shutdown procedures must be known before excavation near live heating mains commences.
The heat network operator must be contacted for exact pipe location and isolation arrangements.
District heating is becoming more common in UK cities, so encounters during excavation will increase.

Scalding burns	Water at 120°C escaping from a damaged pipe causes instant severe scalding burns on contact with skin.
Detection difficulty	Pre-insulated pipes can be hard to detect and distinguish from other utilities using standard survey methods.
Growing network	District heating expansion means construction workers will encounter these services more frequently.

Do

Don't

Contact the heat network operator to confirm pipe locations before any excavation
Use service plans, CAT and Genny, and trial holes to locate district heating pipes
Hand dig within the safe zone of a confirmed district heating pipe location
Brief the excavation team on the scalding hazard from hot water under pressure
Know the emergency shutdown procedure for the district heating network before digging
Maintain a safe exclusion distance from the pipe during all excavation activities
Report any damage to the pipe outer casing, insulation, or leak detection wire
Wear appropriate PPE including long sleeves when working near exposed heating pipes
Coordinate with the heat network operator for isolation if the pipe must be exposed
Mark confirmed district heating pipe locations clearly on the ground surface

DON'T use mechanical excavation within the safe zone of a district heating pipe
DON'T assume standard CAT signals correctly identify district heating pipe locations
DON'T ignore the possibility of district heating pipes — check with the network operator
DON'T approach a damaged district heating pipe that is leaking hot water or steam
DON'T excavate near live heating mains without knowing the emergency shutdown procedure
DON'T touch exposed pre-insulated pipes — the surface may be hot enough to cause burns
DON'T damage the outer casing or leak detection wires during excavation near the pipe
DON'T backfill around exposed district heating pipes without operator approval
DON'T allow workers into an excavation where a hot pipe has been struck or is leaking
DON'T confuse district heating pipes with standard water mains — the hazard is very different

See also: District Heating Pipe Installation | Service Strike Emergency Procedure

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