Sanitary Appliances Flashcards
Sanitary appliances required to fulfill what?
specialised functions
in sanitary appliances, water is supplied from?
water main or cold/hot storage vessel
essential that supply of water is not contaminated by?
foul water
What is foul water?
waste water
Why are the taps designed to discharge above the flooding level of the appliance
to prevent risk of back siphonage of foul
water into the supply pipe
Sanitary appliances must have what surfaces?
durable,easily- cleaned and non-absorbent
slop hopper sink also known as?
sluice sink
what are sluice sink used for? usually can be found where?
fill pails and wash mops, usually found in hospitals and industrial or commercial laundry and cleaning rooms
How foul air from drain and sewer is prevented from penetrating into the buildings?
by applying a water trap to all sanitary appliances
the format of outline of tubular trap follows the letter?
P and S
the outlet of P must be slightly?
less horizontal(2 1/2 degree)
the outlet of S trap must be
vertical
the depth of seal must be retained at?
not less than 25mm
length of trap forWC and guilles
50mm
length of trap for other sanitary appliances other than WCs with waste pipe 50mm nominal diameter or less
75mm
length of trap for sinks, bath and showers
38mm
what is the most obvious loss of water seal
leakage due to defective fittings and poor workmanship, or by poor system design or installation
what is self siphonage? what are causes?
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
induced siphonage
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.
back pressure
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.
capillary action
a piece of rag, string or hair caught in the trap outlet
wavering out
gusts of wind blowing over top of the stack, creating partial vacuum ,disturbing water seal
how to fix water seal problem?
resealing or anti siphon trap
McAlpine trap
reserve chamber, water is retained as siphonage occur, After siphonage , the retained water descends to reseal the water trap
