Test Lesson

Commissioning cold water systems and components
missioning cold water systems and components

4 documents must be followed when commissioning:

The water supply regulations 1999

British standard BS 6700 and BS EN 806

Building regulation approved doc G1 and G2

Manufacturer's instructions of any equipment and appliances

Inadequate commissioning, system flushing and maintenance operations can affect the quality of
drinking water. Debris and swarf can cause pipes to block and promote bacterial growth.

Soundness testing

❏

Visual inspections should be done before testing the system. This can include
checking all open ends are capped off, all connections have been made properly
and nuts are tight

❏

System must then be filled with fluid cat 1 water. Filling the system in stages allows
time to check for leaks stage by stage

❏

When the system has been filled another visual inspection should occur to check
for leaks

❏

Pressure testing can then commence and should be tested to 1 and a half times
working pressure

Soundness testing

Soundness testing is the process of filling
pipework in order to test a systems
integrity before fully livening it up,
soundness testing can be done in multiple
ways, some outlined below.

Regulation 12 (Water regs)

Regulation 12 of the water regulations requires that any system must withstand an
internal water pressure no less than 1 and a half times the maximum operating
pressure.

E.g. 2 bar x 1.5 = a testing pressure of 3 bar.

Reg 12 also states that systems that do not contain any plastic pipework can be
tested to 1 and a half times working pressure but must be left for 30 minutes to
allow for temperature stabilisation and then a further hour with no visible pressure
loss.

While systems containing plastic must follow test type A and test type B.

Testing systems containing plastic pipework.

Any system that contains plastic pipework must be tested with only 2 acceptable
tests, Test type A and Test type B. They are expanded on in BS 6700

Test type A - System is slowly filled and pressure is raised to 1 bar. Check for leaks.
After 45 mins pressure can be increased to 1.5 x normal working pressure for 15
minutes. The pressure is then released down to ⅓ of the previous and left for a
further 45 minutes.

Test type B - System is slowly filled up to the required pressure and must be
maintained for 30 minutes. The pressure is noted after this time. The test must
continue with no further interference for 30 more minutes. Leave for 2 hours. Test is
successful is pressure loss is less than 0.2 bar.

Pressure testing
pump

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PLANNING AND

PREPARING

(hydraulic pressure test)

Planning the test:

*key point* - Before a pressure test is conducted, a risk assessment should be carried
out. PPE should also be used.

Here are certain factors that should be considered before conducting a pressure test:

❏

Is the test being used appropriate for the service and the building environment?

❏

Will the test leave pockets of water that may cause frost damage or corrosion
later?

❏

Can all valves and equipment withstand the test pressure? If not, these will need to
be removed and temporary pipework installed.

❏

Are there enough operatives available to conduct the test safely?

❏

Can different services be interconnected as a temporary measure to enable
simultaneous testing?

❏

When should the test be started when the size of the system is considered?
Preparation should also be taken into account.

HEALTH AND SAFETY KEY FACT:

Pressure testing involves stored energy, the possibility of
blast and the potential hazards of high velocity missile
formation due to pipe fracture and fitting failure. A safe
system of work should be adopted and a permit to work
sought where necessary.

Preparing for the test:

❏

Check that the high points of the system have an air vent or a tap
to help with the removal of air during the test.

❏

Blank or plug any open ends and isolate any valves at the limit of
the test where the test is being conducted in stages.

❏

Remove any vulnerable equipment and components and install
temporary pipework.

❏

Open the valves within the section to be tested.

HYDRAULIC TEST PROCEDURE:

1.

Using the test pump, begin to fill the system. When full, listen for sounds of escaping
air and visually check for signs of leakage.

2.

Release air from the high points of the systems so the system is completely full of
water.

3.

When the system is full and free of air, pump the system up to the required test
pressure.

4.

If the pressure falls, check that any isolated valves are not passing and visually check
for leaks.

5.

Once the test has proven sound, the test should be witnessed and a signature
obtained on the test certificate.

6.

When the pressure is released, open any air vents and taps before draining down the
system.

7.

Refit any vulnerable pieces of pipework, components and appliances.

Disinfection of cold water
systems

British standard requires that water piping systems
be disinfected in the following circumstances:

-In new installations

-Where large extensions or alterations to systems have been
undertaken

-Where it is suspected that the system has been compromised
by contamination

-Where the system has not been in regular use and regularly
flushed

-Where underground pipework has been installed

The disinfectant types

The disinfectants used must be approved for use by
the drinking water inspectorate (1990) and must
conform to the following standards;

- EN 900 for calcium hypochlorite
- EN 901 for sodium hypochlorite

Key point for disinfection of a system

-The pipework MUST NOT be used during the period of
disinfection and notices MUST be posted AT ALL
OUTLETS or any point where water may be drawn off
whilst the disinfection is in progress

Health and safety

-All operatives should reference the appropriate COSHH
data sheets for the disinfectant chemicals beforehand
and ensure you are wearing the correct PPE for the
process

Calculating system capacity

To get the correct concentration of disinfectant, the total system volume in litres must be calculated.

By doing this you will need this equation : L x W x H (to water line) = volume x 1000= capacity

Calculating the capacity of the pipework involves measuring the pipe installed and what pipe size has been
fitted. The bigger the pipe the more water it will hold.

The calculation is as follows : 3.14 x length x 1000.

In this household we have 22mm
running around the house feeding your
appliances and approximately 75 m in
pipe length by using the calculation we
should show house water the pipe will
hold :

-3.14 x 0.022’ x 75 x 1000 = 113
litres

The cold water storage cistern
measures 2m x 1.5m x 1m to the
water line.

2 x 1.5 x 1 =3m cubed

102

The capacity of copper tube per metre

Tube dimension
(Half hard straight lengths)

Carry capacity (L/M)

15

0.145

22

0.320

28

0.539

Testing for chlorine and disinfection

❏

At the end of a one hour period the chlorine content should be 30ppm at
furthest draw off point and if that is not achieved then the system should be
drained and the process started again

❏

A test consists of a clear plastic tube with water from the system in it. A tablet
is the added which changes the colour of the water depending on chlorine
strength

❏

Heavily chlorinated water is dangerous to wildlife and can cause corrosion if
left

Method of disinfection

1.

Flush the system with water

2.

Calculate cistern capacity and amount of disinfectant

3.

Add disinfectant to cistern while it is filling

4.

Open each draw off until a smell of disinfectant is detected

5.

Add more disinfectant so it is at 50ppm

6.

Oce the system is full the one hour test period can begin

The Flushing procedure for cold water systems and
components not requiring disinfection

In practice, it is almost impossible to effect a complete
drain down of a system, particularly large systems. This in
itself is very detrimental as corrosion can often set in and
this can also cause problems with water contamination.

Flushing should be completed to remove potential
contaminants, such as flux residues, PTFE, excess jointing
compounds and swarf.

Simply filling a system and draining down again does not
constitute a thorough flushing.This will only move any
debris from one point in the system to another. In practice,
the system should be filled and the water run at every
outlet until the water runs completely clear and free of any
discoloration.

The flushing of cold water systems is a requirement of the
British Standards.
All systems must be thoroughly flushed with clean water
direct from the water undertaker’s main supply before
being taken into service.

It is generally accepted that systems should not be left
charged with water once the flushing process has been
completed, especially if the system is not going to be used
immediately, as there is a very real risk that the water
within the system could become stagnant.

Therefore, to minimise the risk of corrosion and water
quality problems you should leave systems completely full
and flush through at regular intervals of no less than twice
weekly, by opening all terminal fittings until the system has
been taken permanently into operation. If this is the case,
then provision for frost protection must be made.

Dealing with defects with cold water systems when
commissioning.

Systems that do not meet correct installation requirements: such as incorrect
flow rates and pressures.This could be because you have installed the wrong size
of pipe; or to many fittings/ incorrect valves causing pipework restrictions.

Poor installation techniques: such as noise when filling, this could be caused by
incorrectly clipping your pipe work/ wrong clipping distances. Undue warming of
cold water pipe work this is when you have installed the cold to close to the
heating or hot water pipes.

Contamination

This covers ways cold water systems can become contaminate including:

-Insects and vermin into stored water

-Ingress of debris during installation

-Poor installation

-Undue warming of the cold water

This also covers microbiological contamination.

Microbiological contaminations

HSE state that water must not exceed 20 degrees celsius.

Things like leaks can promote mould growth. Undue warmth can cause development of
Legionella pneumophila, E. coli and Pseudomonas.

E. coli

Legionella

Pseudomonas

Commissioning & Notification of works carried
out

Notification of installations must be given to the correct authorities
so they can check it complies with regulations and the installation has
no danger to health

The water undertaker must be notified

The local building control office must be notified

This must take place within 5 days after work completion

Commissioning records for large cold water systems

Should be kept for reference during maintenance and repair and to enure
that the system meets design specification.

Information that should be included on the record

Date time and name of the commission engineer, location of installation,amount of
cold water storage, the type of pressure test carried out , flow rates and pressure
at the outlet.

Hand over procedure: the customer will need all the paper work regarding the
installation: manufacture instructions, servicing manuals. The customer will need
to be shown around the installation, also emergency isolation points on the
system should be pointed out.