New mains, supplied and laid
Scotland-wide supply, lay, construction and testing of new water, fire, sprinkler and rising mains as a WIRS accredited contractor.
Service
Swabbing, chlorination and sampling
Swabbing, chlorination, dechlorination and UKAS-lab bacteriological sampling in one package, so the main is clean, disinfected and proven safe before it goes live.
- Swab & flush
- Chlorination
- Dechlorination
- UKAS sampling
Service overview
Before a new main is connected and made live, the water authority needs to see a chlorination certificate and the sample results from the microbiological test. That is the proof the new pipework is free from bacteria that could cause illness to the people it serves. Pressure Test Scotland offers a fast and complete package for the whole disinfection and sampling stage.
The process starts with pre-flushing and swabbing the pipe, then the introduction of a high-strength chlorine solution, a period of standing, further flushing and a second period of standing, before we collect the final on-site parameters for chlorine residual and take the water sample. The microbiological samples are taken to and analysed by a UKAS accredited laboratory, so the result carries the weight the water authority expects.
Key benefits
- One package, start to sampleSwabbing, chlorination, dechlorination and sampling handled together, so nothing is missed between stages.
- Swabbed and flushed firstAir, spoil and debris cleared out of the pipe before disinfection, because a dirty pipe fails its sample.
- High-strength disinfectionA high-strength chlorine solution introduced and held for the required contact time, then flushed.
- Dechlorinated to residualThe main is dechlorinated and flushed down to the network residual, so it is safe to connect.
- UKAS accredited labBacteriological samples analysed by a UKAS accredited laboratory, the result the water authority accepts.
- First-time pass, our cost if notWe manage the residual carefully to pass first time, and usually carry any re-chlorination and re-sampling at our own cost.
What's included
- Pre-flush and foam swab of the main
- High-strength chlorine dosing
- Held for the required contact time
- Dechlorination and flush to residual
- On-site chlorine residual readings
- UKAS accredited bacteriological sampling
- 01
Swabbing and pre-commission cleaning
A foam swab is driven through the length of the main to push out trapped air and the debris left behind during installation.
Stage focus:
- Foam swabbing
- Air removal
- Debris clearance
- 02
Hydrostatic pressure testing
The main is filled, brought up to working pressure and held, then monitored against the allowable loss for the pipe and length. We test PE, MDPE, barrier and ductile.
Stage focus:
- PE and MDPE
- Barrier and ductile
- Working pressure
- 03
Chlorination and disinfection
A dosed disinfection solution is introduced and held in the main for the required contact time, then dechlorinated and flushed down to the network residual.
Stage focus:
- Dosing
- Contact time
- Dechlorination
- 04
Bacteriological sampling
Water samples are drawn from the disinfected main and sent for laboratory analysis against the potable standard.
Stage focus:
- UKAS lab
- Coliforms & E. coli
- Potable standard
- 05
Certification
The results from every stage are assembled into the auditable certificate pack that Scottish Water accepts to permit connection.
Stage focus:
- Certificate pack
- Audit trail
- Scottish Water accepted
Why does a new main need chlorination and sampling?
Before connecting a main to make it live, the water authority needs a chlorination certificate and microbiological sample results. This demonstrates the new pipework is free from bacteria that could cause illness to those it serves. A main cannot be signed off for connection without it.
What does the chlorination process involve?
Pre-flushing and swabbing the pipe, then introducing a high-strength chlorine solution, a period of standing, further flushing, and a second period of standing. We then collect the final on-site chlorine residual readings and take the water sample for the lab.
Where are the samples analysed?
The microbiological samples are taken to and analysed by a UKAS accredited laboratory. The lab tests for coliforms, E. coli and total viable counts, and the result is what the water authority accepts as proof the main is safe to connect.
What happens if a sample fails?
The main is re-chlorinated, dechlorinated, flushed and re-sampled, which costs days, not hours. We manage the disinfection and residual carefully the first time to get a first-time pass, and we usually carry any re-chlorination and re-sampling at our own cost and time.
Related services
Often needed alongside
Pressure testing
Data-logged hydrostatic testing to prove the main holds working pressure before tie-in.
Certification and tie-ins
The chlorination certificate and sample results pack, plus primary tie-ins to existing Scottish Water infrastructure.
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Email them over or give us a call. You get a clear price, a date that fits your programme, and the compliance pack at the end. No pressure, no jargon.