5 Cold Water Systems Testing and Decommissioning

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Questions and Answers

What should be done with pipework that is no longer in use?

Fill the pipework with concrete

Leave it as it is without any modifications

Remove and leave the pipework unsealed

Cap the pipework at the end of branches (correct)

What is a passive dead leg in plumbing?

A pipe that delivers hot water without drawing cold water first

A section of pipework where water cannot be drawn off (correct)

A section of pipe that allows water flow at all times

A pipe that is regularly maintained and serviced

Why is it important to label valves after isolation during maintenance?

To keep track of which valves need replacement

To inform customers about the ongoing work

To avoid turning on the valve while work is ongoing (correct)

To prevent unauthorized access to the valves

What is the best practice when draining a cold water system?

Using a DOV and hose pipe from the lowest point Signup and view all the answers

What should you do if you find a leak during testing?

Stop the test and address the leak Signup and view all the answers

What is the purpose of flushing and disinfecting a system?

To remove debris and prevent contamination Signup and view all the answers

How can you determine if a drain is connected to the mains sewer?

Checking with the local authority Signup and view all the answers

What type of draining involves isolating parts of the system?

Localized draining Signup and view all the answers

What is the first step in soundness testing plastic pipe systems?

Slowly fill the system with water Signup and view all the answers

What should be used as a disinfectant during the flushing process?

Sodium hypochlorite solution Signup and view all the answers

What must be checked after pumping the system to 1 bar for 45 minutes?

Check for loss of pressure Signup and view all the answers

What is a consequence of stagnant water in a system?

Bacterial growth Signup and view all the answers

What is the final step in the commissioning process before handing over to the customer?

Complete any documentation Signup and view all the answers

During flushing and disinfecting, after adding chlorine, what should be done next?

Test chlorine levels at each outlet Signup and view all the answers

What is the initial step a plumber must perform before conducting a soundness test?

Visual inspection of the system Signup and view all the answers

How long should the system be allowed to stand for temperature stabilization during the soundness test?

30 minutes Signup and view all the answers

Which of the following describes temporary decommissioning?

System remains isolated until repairs are completed Signup and view all the answers

What is a risk at temperatures between 20°C and 46°C in plumbing systems?

High risk of legionella bacteria growth Signup and view all the answers

To what pressure should the system be pumped during the hydraulic testing of a system that operates at 3BAR?

4.5BAR Signup and view all the answers

What must be checked after the pressure is applied during the soundness test?

Check for any pressure drop Signup and view all the answers

What procedure follows after soundness testing and confirming no leaks?

Hand over to the customer Signup and view all the answers

What type of pipe materials require different soundness tests compared to rigid pipe (copper and steel)?

Flexible plastic pipes Signup and view all the answers

What is the importance of disinfecting a cold water system before commissioning?

To ensure the system is cleaned internally Signup and view all the answers

What should be done if a pressure drop is detected during the soundness test?

Rectify the issue and retest Signup and view all the answers

What is the primary purpose of conducting a soundness test on a cold water system?

To check for leaks and ensure system integrity Signup and view all the answers

During the soundness test for rigid pipes, how long should the system be left to stabilize temperature?

30 minutes Signup and view all the answers

What should be the first action when performing a soundness test on plastic pipe systems?

Slowly fill the system with water Signup and view all the answers

What must be done after filling the system with water before carrying out the soundness test?

Verify all visual checks are completed Signup and view all the answers

Which of the following steps is essential to ensuring effective flushing and disinfecting of a new system?

Run water until clear of debris and color Signup and view all the answers

What pressure should a system designed to operate at 3BAR be tested at during the hydraulic soundness test?

4.5 BAR Signup and view all the answers

What is the maximum pressure the system should be maintained at during a soundness test according to standard procedures?

1.5 times the working pressure Signup and view all the answers

Which of the following is not a recommended practice after completing a soundness test?

Handing over without further checks Signup and view all the answers

How should a plumber confirm that all joints have been checked before soundness testing?

By conducting a visual inspection and ensuring tight connections Signup and view all the answers

What is included in the initial steps before performing any soundness testing?

Carrying out a visual inspection of the system Signup and view all the answers

Which of these conditions can lead to bacterial growth in a plumbing system?

Stagnation of water Signup and view all the answers

During decommissioning, what is the primary action taken to halt operation?

Isolate the system at the incoming mains stop valve Signup and view all the answers

What should be the first step in the commissioning process after installing a cold water system?

Visually inspecting for issues Signup and view all the answers

What is a key reason for testing flow rates at outlets during commissioning?

To ensure adequate supply and pressure Signup and view all the answers

If a plumbing system shows a pressure drop during the soundness test, what action should be taken?

Identify and rectify the issue before retesting Signup and view all the answers

What factor must be controlled during the flushing process to minimize risks?

Presence of chlorine Signup and view all the answers

What should be done with the pipework when a whole system is decommissioned?

Remove and cap the pipework above the stop valve Signup and view all the answers

What is an active dead leg in plumbing systems?

A section of pipe where cold water must be drawn before hot water Signup and view all the answers

Which of the following describes the best practice for draining a cold water system?

Drain from the lowest point of the system using a DOV and hose pipe Signup and view all the answers

What should be used to temporarily cap pipework during maintenance?

Bung kits to seal safely Signup and view all the answers

Why is it necessary to inform customers when decommissioning a system?

To help them understand changes and potential implications Signup and view all the answers

How should one verify that a system has properly drained?

By checking at various outlets to ensure no water remains Signup and view all the answers

What is a consequence of having stagnant water in plumbing systems?

Development of bacterial growth Signup and view all the answers

What is a significant step to take when capping branches of pipework?

Label each valve after isolation to prevent confusion Signup and view all the answers

Study Notes

Key Requirements of Testing and Decommissioning Domestic Cold Water Systems

The commissioning process for a cold water installation involves several steps: visual inspection, soundness test, flushing, disinfecting, and hand-over to customer.
Soundness tests vary depending on pipe material (rigid/copper, steel, or plastic).
Before any tests, plumbing professionals must visually check for open ends, properly soldered and compressed joints, and secured clips.
Rigid pipe (copper and steel) soundness tests involve slowly filling the system with water, leaving it to stabilize, attaching a hydraulic test bucket, and pumping up to 1.5 times the working pressure (e.g., 4.5 bar if the system works at 3 bar). The system should be monitored for at least one hour for pressure drops.
Plastic pipe (polybutylene) soundness tests involve slowly filling, checking for leaks, pumping to 1 bar, checking for loss of pressure after 45 minutes, increasing pressure to 1.5 times the working pressure for 15 minutes, checking for pressure loss, and reducing to one-third for another 45 minutes while monitoring for pressure loss.

Flushing and Disinfecting

After installation, the system must be flushed to remove debris. Flush the system thoroughly at each outlet until no chlorine is present.
Re-fill the system with water and drain it from the lowest point.
Open the kitchen tap to run water until debris is no longer present. Repeat this at all outlets.
Add disinfectant (Sodium Hypochlorite or Chlorine) to the system for at least one hour, as detailed in BS EN 806 standards.

Commissioning

Ensure the system is completely filled.
Adjust flow rates at each outlet for cold and warm water (in liters/min or liters/sec).
Check the pressure at each outlet (in bar).
Inspect insulation and piping.
Check and label valves.
Complete all documentation.
Hand over the system to the customer.

Decommissioning

Inform the customer or work colleagues if decommissioning is required.
Cap the pipework at the end of branches.
Label valves for isolation and warn against turning them on.
Drain the water thoroughly at each outlet.
Verify proper connection of the drain system to the main sewer if necessary. Ensure this connection is verified.

Dead Legs

Passive dead legs: portions of the pipework through which water cannot flow, potentially leading to bacterial growth.
Active dead legs: sections requiring cold water drainage before hot water drainage, often leading to water waste.

Draining Cold Water Systems

Common draining techniques include localised, part, or fully draining.
Always drain from the lowest point using a drain hose.
Minimize water waste during maintenance or replacement.
Isolating parts of the system may be necessary.
Bung kits can be used for safe drainage.

Soundness Testing (Questions)

Why are soundness tests necessary? To identify leaks and ensure the integrity of the water system, preventing potential damage and water loss.
What should be done if a leak is discovered during a test? Isolate the affected section, repair the leak, and retest the system to verify the repair.

Flushing & Disinfecting (Questions)

Why is it necessary to flush and disinfect the system? To remove debris and contaminants, and ensure the system is safe for use and free of bacterial growth.

Decommissioning (Questions)

What is temporary decommissioning? A temporary isolation of the system for work or repairs.
What is permanent decommissioning? Permanent removal of the system or appliance.
What are the 3 types of draining? Local drainage, partial drainage, and fully draining.

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Description

This quiz covers the key requirements for testing and decommissioning domestic cold water systems. It includes steps for commissioning, soundness tests for different pipe materials, and important visual inspections prior to testing. Understand the processes involved to ensure compliance and safety in plumbing installations.