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Above ground drainage part 4

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Above ground drainage part 4

  1. 1. PART 4 Practice plumbing exams © www.practiceplumbingexams.com
  2. 2. Sanitation Sanitary appliances - Soil Water closets (W C’s):- • Made from vitreous china, glazed fireclay, stainless steel with cisterns also made in plastics • The appliance is usually used in conjunction with a flushing cistern to remove the contents of the bowl or pan • They are normally 400 mm high & may be wall hung, back to wall, high level, low level or close coupled Practice plumbing exams © www.practiceplumbingexams.com
  3. 3. Sanitation Sanitary appliances - Soil W C’s:- • 2 types of pan available – Washdown & Syphonic  Washdown (most popular) – Where the pan is cleaned only by the force & volume of the flush water. Washdown pans have 50 mm water seal with a bowl shaped to give a large water area with a minimum of fouling & efficient cleaning  Syphonic (quiet in operation) – May be single or double trap. Both operate by creating a negative pressure below the trap seal. Single trap has a restriction in the outlet, whilst the double trap creates a negative pressure between the 2 traps by drawing the air from the void when the cistern if flushed Practice plumbing exams © www.practiceplumbingexams.com
  4. 4. Sanitation Sanitary appliances - Soil W C’s:- • 50 mm seal depth with only P traps now available • Around 100 mm dia. outlet to soil pipe • Floor fixings vary from brass screws with soft washer to plastic brackets screwed to floor then pan fixed to brackets & capped • Wall mounted need to be well supported to ‘solid’ wall Practice plumbing exams © www.practiceplumbingexams.com
  5. 5. Sanitation Sanitary appliances - Soil W C Cisterns:- • May be high level (around 2 m’s high with long flush pipe & chain pull), or low level/close coupled with short, or no flush pipe & handle/button press • Isolation valve should be fitted immediately before float valve • Float valve to be part 2/3 or 4 with freely moving & adjustable float to suit water volume • From Jan 2001 volume of flush now 6 litres with dual flush being favoured again. Before then 7.5 & 9 litre flushes • From Jan 2001 overflow pipe can “discharge in a prominent position or other equally effective device” i.e. can now discharge to flush pipe Practice plumbing exams © www.practiceplumbingexams.com
  6. 6. Sanitation Sanitary appliances - Soil W C Cisterns:- • Water enters cistern via float operated ball valve & water level is regulated by this device • Overflow pipe (twice the dia. of inlet) situated 1 dia. down • When operated, the flushing device empties the cistern contents down the flush pipe • Types of flushing device are:-  Bell type – used in high level cisterns in the past. C.I. bell is lifted & then dropped to form negative pressure at the top of the flush pipe. Syphon is then set up until air gets under the bell to break the syphon Practice plumbing exams © www.practiceplumbingexams.com
  7. 7. Sanitation Sanitary appliances - Soil W C Cisterns:-  Syphon type – pressing the handle down pulls a flexible diaphragm up to lift a body of water over a U bend which fills the syphon with water & starts the syphon. This continues until the low water level allows air to enter & break the syphon  Plug type – becoming more popular with the re- introduction of dual flush. By pressing down a button on top of the cistern, one of two plugs are lifted allowing water to fall down the flush pipe until the falling water level then allows the plug back into place. The two plugs are set to differing heights to permit two volumes of flush Practice plumbing exams © www.practiceplumbingexams.com
  8. 8. Sanitation Sanitary appliances - Soil Urinals:- • May be made from vitreous china, glazed earthenware, stainless steel & plastics • May be in the form of slab, stalls, trough or bowls • Slabs & troughs have sparge pipes which discharge the flushing water over the appliance, stalls & bowls have individual spreaders • Waste connections vary in size according to the flow from 2 ½” for slabs to 1 ¼” for individual bowls • Provision must be made for future access/cleaning as they block up frequently • Nearly all urinals utilise automatic flushing cisterns Practice plumbing exams © www.practiceplumbingexams.com
  9. 9. Sanitation Sanitary appliances - Soil Automatic flushing cisterns:-  Made from materials similar to W C cisterns  Only used on urinals to provide regular/rate of use flush  Cistern fills slowly through pet cock/orifice/cisternmiser etc. (no float valve)  When water reaches set level, an automatic flushing device will empty the cistern contents to the flush pipe  When cistern fills, air becomes trapped between cistern water & the bottom trap. As the water level rises, it starts to trickle over the lip & as it falls it draws with it air from the chamber. The reduced air pressure & the rising water level will then start a syphon Practice plumbing exams © www.practiceplumbingexams.com
  10. 10. Sanitation Sanitary appliances - Soil Slop hopper or slop sink:- • Are made from the same materials as in W C’s • Appliance is similar to WC but used in hospitals etc. to wash out bed pans • Fitted with hinged grating over pan & bib taps above to wash out bed pan • Traps & outlets etc. – same as W C’s Practice plumbing exams © www.practiceplumbingexams.com

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