Building Services 1 (BLD 60403)

HOT WATER SUPPLY SYSTEM (PART 2)

LECTURE OVERVIEW

1. Pipe materials for hot water supply

2. Hot water system for larger buildings

3. Hot water system for high rise buildings

1. PIPE AND MATERIALS

Choose carefully.

Pipes are classified by their pressure rating at

20°C.

For example, PN16 is rated for a pressure of 1600

kPa at 20°C.

The allowable working pressure will decrease

with temperature

The working pressure and max. temperature

vary with different materials.

kPa = kilopascal – Standard International (SI) derived

unit of pressure

Acceptable materials:-

Copper pipe.

Polybutylene (PB) and cross-linked polyethylene (PEX)

piping systems - if the temperature and pressure

limitations of those materials are not exceeded by the

system under normal operating conditions.

C

Copper pipes

PB pipes

PEX pipes

Copper pipes use as a transition/switch between a heat

source and distribution pipe

This allows heat conducted down the pipe from the

heat source (solar panel or water storage cylinder).

Few grades of cross-linked polyethylene (PEX)

pipe available

reasonable price

tolerate 100°C water for any significant length of

time.

PEX piping gives the following maximum

allowable working temperatures and pressures:

Central heating 300 kPa at 92°C

Hot water 600 kPa at 65°C

Cold water 1200 kPa at 20°C

Cross-linked polyethylene can withstand 114°C

intermittently for short periods.

UNDERFLOOR

HEATING

2. HOT WATER SYSTEM FOR LARGE

BUILDING

Centralised System for A Large Building

Each floor is zoned with valves, so that a repair on one

floor may be carried out without draining the whole of

the pipework

3. HOT WATER SYSTEM FOR HIGH RISE

BUILDINGS

Floors are zoned

The purpose of zoning is to maintain the pressure of

the hot water supply

Head tank improves the flow of hot water to the taps

on the upper floors of each zone.

Calorifier

Pump

THANK YOU

CHILDREN ARE QUICK AND ALWAYS SPEAK THEIR MINDS

Teacher: George Washington not only chopped down his father’s cherry tree, but also

admitted it. Now, Louis, do you know why his father didn’t punish him?

Louis: Because George still had the axe in his hand……