FEATURE 25
Because the unit is far larger than traps , they can gather more FOG over a longer period , again dependant on the amount of grease generated .
In both cases the local authority may well have by laws addressing these products so always wise to check with them .
SANS 10252-2 Water supply and drainage for buildings . Part 2 : Drainage installations for buildings . Whilst no standards exist for either product , provision is made for them in this standard , which is compulsory , making the installation directions compulsory .
Section 4.3 Provision of grease and light-liquid interceptors . 4.3.1 a grease interceptor shall be provided to take the discharge from any sanitary fixture or appliance where the discharge of such a fixture or appliance could contain grease , fat , or vegetable oil , a . where such discharge will drain directly to a French drain , or b . in quantities that could 1 . Cause an obstruction to the flow in any drain , or 2 . Interfere with the efficient operation of any sewerage treatment or disposal system .
4.3.2 Provision of light-liquid interceptors A light-liquid interceptor shall be provided to take the waste-water discharge from a . Any sanitary fixture or appliance in a building where such a discharge could contain unacceptable levels of liquid that could , 1 . Affect the flow in any drain , sewer , or 2 . interfere with the efficient operation of any sewage treatment of disposal system , and b . any paved area upon which light-liquids or washing water contaminated with such liquids can fall . Such area shall slope at a gradient of at least 1 in 200 from all sides towards a floor drain gulley , which shall discharge to the light-liquid interceptor .
5.2.7 Grease interceptors 5.2.7.1 any grease interceptor required for a given building or commercial establishments shall serve only that building or establishment .
5.2.7.2 any grease interceptor shall be so located that it is easily accessible for inspection and cleaning purposes , and that intercepted FOG can be removed hygienically . The location shall be such that , a . there will be no need to use ladders or to move bulky objects to check or service it , and b . it is possible to completely empty and clean the interceptor .
5.2.7.5 Any grease interceptor shall be vented to prevent it from becoming air locked . The design and construction of the interceptor shall be such that the air space above the separation compartment is ventilated through the inlet pipe .
5.2.7.6 . Only wastewater that requires separation shall be discharged into a grease interceptor or sludge trap . Water and wastewater that promotes the process of separation may also be discharged through such a trap .
5.2.8 Light-liquid interceptors . 5.2.8.1 Access to the automatic closure valves of light-liquid interceptors fitted with such valves shall be secured by a seal .
5.2.8.2 the air space of the light-liquid interceptor shall not be ventilated , but the outlet pipe from the interceptor shall be ventilated with a vent pipe that has a diameter at least half that of the outlet pipe .
5.2.8.3Light -liquid interceptors shall be covered in a tight and traffic safe manner . Covers shall . a . be non-flammable . b . not be secured . And c . permit the removal of fine sludge and light liquids .
5.2.8.4 it shall not be possible . a . to draw wastewater off through the outlet pipe to such an extent that the separated light liquid reaches the outlet pipe , and \ b . for the intercepted light liquid to flow back into the inlet pipe .
5.2.8.5 only wastewater that requires separation shall discharge into a light-liquid interceptor , and the interceptor shall discharge into a drain .
5.2.8.6 Liquid entry into the interceptor shall be through a floor drain or floor channel and a sludge trap . The sludge trap shall be . a . installed before the liquid enters the interceptor , to retain substances capable of precipitating , and b . so designed and installed that it can be easily cleaned when necessary .
It must be noted that most clauses are accompanied by a commentary and diagrams that explain flow rates , flow through and other points that explain the clause in more detail . It is important to refer to the commentaries as it is important to have the full SANS 10252 -2 document available from www . sabs . co . za . PA
5.2.7.3 Unless otherwise approved , a grease interceptor situated below ground outside a building shall not be located within 1.0m of any building foundation or property boundary .
5.2.7.4 all parts of the grease interceptor , including the inlet and outlet sockets , shall be easily accessible for cleaning purposes . The interceptor shall be fitted with a removable lid or a manhole cover that permits easy and effective removal of grease , fat , solid matter or fine sludge , and that seals airtight .
“ Using these two words in one sentence for grease traps and grease interceptors is not normally a good thing .”
April 2021 Volume 27 I Number 2 www . plumbingafrica . co . za