Water hardness and the building regs

[hadstock]

I've got 3 questions on water hardness and the building regs:

1. The Domestic Heating Compliance Guide says in Table 9 that if mains water hardness exceeds 200 ppm then provision for treatment should be made. Our water company's website says that our area has a hardness of 150 ppm as calcium and 275 as calcium carbonate. Which of these are the building regs referring to?

2. Presumably 'provision for treatment should be made' means 'provision for treatment must be made'?

3. The only Building Regs Compliance certificate that we have describes the works as 'commission pressure-jet appliance installation'. I would have thought that 'commissioning' just meant final testing/checking out. Or would it also cover things like design (and therefore checking for provision of water softening treatment where required)?

All help gratefully received.

 

[crockett]

If it says 'should', it means should. If it says 'Must', it means definitely!!

Cacium carbonate is temporary hardness , calcium sulphate is permanent hardness

Commissioning is exactly what you said, inspection and testing for initial use.

 

[hadstock]

Thanks for the reply and the explanation about calcium - but which of the two is the Domestic Heating Compliance Guide Table 9 referring to?

 

[Onetap]

Total hardness, 275 ppm.

150 ppm I'd think refers to the milligrams of calcium per litre of water, 275 is the milligrams of CaCO3 (I think) in 1 litre.

It is most relevant to combi boilers in which the plate heat exchanger will scale up if supplied with hard water. The PHX has narrow water ways which will become blocked.

Although it also applies to water storage cylinders, the scale deposits will drop to the bottom and don't significantly affect efficiency in the life of the cylinder.