Mapi pipe chambers with double welded bottom meet the demands for access and inspection chambers in high-traffic areas, greater installation depths and in the presence of groundwater.
Due to robust welded construction they can be used in areas where predicted level of groundwater can be as high as 5,0 m above inspection chamber bottom.
Nominal chamber sizes are ID1000, ID800, ID600, ID500 and ID400mm. Made either of polyethylene or polypropylene.
Static and dynamic stress to the lid is not transferred directly to the body of the chamber, instead a finished reinforced concrete slab redirects it to a fortified filling around the chamber.
Description of welded bottom inspection chambers
MAPI PIPE inspection chambers consist of:
The body of the chameber
Material can be either polyethylene or polypropylene, as long as all elements in a single chamber are made of the same material. Exceptions are ladders or stairs which are made of aluminium or stainless steel.
Individual components are joined together by extrusion welding.
Chamber bottom is manufactured according to project. Any number of connections can be made, at different angles according to the outflow. The fold of the main flow bed (inflow, outflow) is always in the middle of the chamber. Additional connections are made roughly 20mm above main flow bed. It is possible to connect sewage pies from DN160 up to DN1000.
Chamber bottom is constructed out of pipe elements of suitable diameter and plates which are extrusion welded together. Depending on predicted groundwater levels, extra reinforcement can be added on the bottom side of the chamber.
The bottom of the chamber can be sealed with additional plate, making it a secondary bottom. This type of inspection chamber is known by different names, ie: »chamber with dual layer bottom« or »double bottom camber«.
The purpose of secondary bottom is:
to seal the empty space between the bed and the primary bottom that forms underneath certain type of shafts. Such empty space usually can not be filled and properly compacted, fractions of surrounding fill material is being rinsed into said space, making it weaker in the long run.
to ensure the stability of the chamber during transport and and installation, which can be a weakness of chambers made entirely by rotomoulding.
Structure bodied Mapikan or Terakan sewage pipes are used as inspection chamber bodies. Because of that radial rigidity greatly exceeds standard demands and it is also several times stronger than rigidity of any rotomoulded elements.
On the upper end, the chamber body can be closed with a rotomoulded cone, or it can be left as »wide mouth«. Whichever the case, it must be ensured that static and dynamic stress to the lid is not transferred directly to the body of the chamber, instead a finished re-enforced concrete slab should redirect it to a fortified filling around the chamber.
Using the ladder eases the entry into inspection chamber. Steps of aluminium alloy or stainless steel are also used.