Sanitary Appliances

Question 1

Sanitary appliances required to fulfill what?

Answer 1

specialised functions

Question 2

in sanitary appliances, water is supplied from?

Answer 2

water main or cold/hot storage vessel

Question 3

essential that supply of water is not contaminated by?

Answer 3

foul water

Question 4

What is foul water?

Answer 4

waste water

Question 5

Why are the taps designed to discharge above the flooding level of the appliance

Answer 5

to prevent risk of back siphonage of foul

water into the supply pipe

Question 6

Sanitary appliances must have what surfaces?

Answer 6

durable,easily- cleaned and non-absorbent

Question 7

slop hopper sink also known as?

Answer 7

sluice sink

Question 8

what are sluice sink used for? usually can be found where?

Answer 8

fill pails and wash mops, usually found in hospitals and industrial or commercial laundry and cleaning rooms

Question 9

How foul air from drain and sewer is prevented from penetrating into the buildings?

Answer 9

by applying a water trap to all sanitary appliances

Question 10

the format of outline of tubular trap follows the letter?

Answer 10

P and S

Question 11

the outlet of P must be slightly?

Answer 11

less horizontal(2 1/2 degree)

Question 12

the outlet of S trap must be

Answer 12

vertical

Question 13

the depth of seal must be retained at?

Answer 13

not less than 25mm

Question 14

length of trap forWC and guilles

Answer 14

50mm

Question 15

length of trap for other sanitary appliances other than WCs with waste pipe 50mm nominal diameter or less

Answer 15

75mm

Question 16

length of trap for sinks, bath and showers

Answer 16

38mm

Question 17

what is the most obvious loss of water seal

Answer 17

leakage due to defective fittings and poor workmanship, or by poor system design or installation

Question 18

what is self siphonage? what are causes?

Answer 18

as appliances discharge, the water fills the waste pipe and creates vacuum to draw out the seal. Causes, waste pipe are too long, too steep or too small in diameter

Question 19

induced siphonage

Answer 19

This is caused by discharge of water from another sanitary appliance connected to the same discharge pipe. In either a vertical or horizontal main waste pipe, as water flows down the pipe and passes the branch pipe connected to it, it draws air from it, thus creating a partial vacuum and subsequently siphonage of the trap takes place.

Question 20

back pressure

Answer 20

occurs in high rise building, when water is discharged down to the main discharged stack, air is compressed at the base of the stack. A waste pipe connected to the stack in the pressure zone may have the seal of the trap lost by the compressed air forcing out the water.
Detergent foam increases the risk of compression.

Question 21

capillary action

Answer 21

a piece of rag, string or hair caught in the trap outlet

Question 22

wavering out

Answer 22

gusts of wind blowing over top of the stack, creating partial vacuum ,disturbing water seal

Question 23

how to fix water seal problem?

Answer 23

resealing or anti siphon trap

Question 24

McAlpine trap

Answer 24

reserve chamber, water is retained as siphonage occur, After siphonage , the retained water descends to reseal the water trap

Question 25

Grevak trap

Answer 25

contains anti-siphonage pipe, where air flows through to break any siphonage action.

Question 26

Econa trap contains? function?

Answer 26

cylinder, same function like McAlpine

Question 27

anti-siphon trap

Answer 27

when siphonage occur, the valve on the outlet open and air flows through it which helps to maintain normal pressure,, preventing water seal loss.

Question 28

to ensure anti-siphon to function correctly, waht must be done?

Answer 28

regular maintenance

Question 29

self sealing waste valve developed by who?

Answer 29

Hepworth Building Products

Question 30

self sealing waste valve for?

Answer 30

all sanitary appliances which have 32mm-40mm nominal diameter

Question 31

what is self sealing waste valve?

Answer 31

straight section of pipe with flexible tubular sealed membrane

Question 32

advatages of self sealing waste valve?

Answer 32

N 3S F V A

• no siphonage with full bore discharged
• full bore discharged help to clean the pipe
• saving spaces
• saving material and installation time.
• anti-siphon and ventilating are not required
• ranges of appliances does not need auxiliary ventilating to stacks
• smaller diameter is possible