PLUMBING Presentation on Trap Loss Trap Loss At

PLUMBING Presentation on Trap Loss

Trap Loss At the end of this session you should be able to : • Explain what is meant by trap seal loss

Trap Loss Why does Trap seal loss occur ? Trap seal loss occurs when the seal of the trap is lost as a result of poor practice and by not following the regulations with regard to sanitation pipework installation.

Trap Loss There are three main causes of loss of trap seal: • Self siphonage • Induced siphonage • Compression Each one of these is the result of poor installation work

Induced Siphonage • Caused by appliances connecting into a common waste discharge pipe. • This arrangement is not acceptable on primary ventilated stack.

Self Siphonage • Most common in washbasins and steep sided appliances. • Ensuring the waste pipe is at the correct length and fall would avoid this problem

Compression • Usually caused by discharging W. C. higher than the lowest waste connection. • Use large radius bend at base of stack (min 200 mm) • Min 450 mm between invert of the drain and lowest branch waste pipe.

Trap Loss prevention Anti siphon trap

Maximum pipe runs • Observe these maximum pipe lengths and you shouldn’t have a problem. • Loss of the trap seal can also pose a health hazard. Appliances Dia (mm) Min. trap seal depth (mm) Max. length of pipe (m) Pipe Gradient in. Deg ° Max Bends No. Max drop (H) m Washbasin or bidet 32 mm 75 mm 1. 7 m 2. 2 0 0 Washbasin or bidet 40 mm 75 mm 3. 0 m 1. 8 to 4. 4 2 0 Bath or shower 40 mm 50 mm No limit 1. 8 to 9. 0 No limit 1. 5 Bowl urinal 40 mm 50 mm 3. 0 m 1. 8 to 1. 9 No limit 1. 5 Trough urinal 50 mm 75 mm 3. 0 m 1. 8 to 1. 9 No limit 1. 5 Kitchen sink 40 mm 75 mm No limit 1. 8 to 1. 9 No limit 1. 5 Dishwater or washing machine 40 mm 75 mm 3. 0 m 1. 8 to 1. 4 No limit 1. 5 W. C. 110 mm 50 mm No limit 1. 8 min No limit 1. 5

Session Summary • We discussed what the causes of trap loss are. • Looked at each of the causes of trap loss. • How to rectify the problem of trap loss.