PREFORMED INSPECTION
CHAMBERS
Preformed inspection chambers can be used for invert depths of up to 1.2m. The chamber should be placed on suitable compacted material so that it is evenly supported.

When the base is in position the bungs can be removed and pipes inserted as appropriate. The risers are then placed on the base to reach the desired invert. The mastic provided should be used to seal each joint. The top riser can be trimmed to suit finished ground level. It is recommended that the cover and frame are fitted at this point to stop any foreign matter from entering the chamber. Backfilling may then take place around the chamber base and the connecting pipes, using suitable granular material. Backfilling continues to within 160mm of ground level. A concrete plinth is then cast, in which the plastic cover and frame sit.

FIGURE 8A


The straight through channel should be used for
the main flow at all times as illustrated above.
This reduces the likelihood of cross flow and helps
show direction of flow for rodding purposes.


Product codes -
Chamber Base 5494
Sectional Riser 5395


Radius on 90°/160mm inlets improves flow through the chamber.

Product codes -
Chamber Base 5696
Sectional Riser 5395

Figure 8b illustrates some of the alternative
configurations available when using
preformed inspection chambers.


N.B. When turning through 90°, 2Nº x 45º bends
should be used as above.

TABLE 5
INSPECTION CHAMBER 450mm X 110mm - KEY
DIMENSIONS

INSPECTION CHAMBER – KEY DIMENSIONS

Chamber Base Diameter 450mm Invert Depth of Base and 1 Riser 405mm Invert Depth of Base and 2 Risers 580mm Invert Depth of Base and 3 Risers 755mm Invert Depth of Base and 4 Risers 930mm Invert Depth of Base and 5 Risers 1105mm plastic Cover and Frame 25mm

INSPECTION CHAMBER – KEY DIMENSIONS

Chamber Base Diameter 450mm Invert Depth of Base and 1 Riser 430mm Invert Depth of Base and 2 Risers 605mm Invert Depth of Base and 3 Risers 780mm Invert Depth of Base and 4 Risers 955mm Invert Depth of Base and 5 Risers 1130mm plastic Cover and Frame 25mm

INSPECTION CHAMBER – KEY DIMENSIONS

Chamber Base Diameter 280mm Invert Depth of Base 205mm Invert Depth of Base and 1 Riser 395mm Invert Depth of Base and 2 Risers 575mm Plastic Cover and Frame 25mm

SHALLOW ACCESS CHAMBERS

The Brett Martin Shallow Access Chamber is designed for use with 110mm drain and is suitable for invert depths up to a maximum of 600mm.

Two bases are available, the first of which (code 2800) consists of a 45º inlet situated either side of the 110mm dia. dropped channel.The second base (code 2803) offers a 90º change of direction in the main channel.

Joints are made as normal, using a square cut, chamfered 110mm pipe spigot, lubricated with Brett Martin lubricant.

Each Shallow Access Riser (B2801) gives an increase in invert depth of 185mm. These, however, can be easily cut down to achieve the desired height using a fine tooth saw and the strengthening ribs as a guide. A maximum of 2 risers will give an invert depth of 575mm, plus the cover and frame (B2802) which has an effective depth of 25mm, giving a maximum invert depth of 600mm.

Joints from riser to base, and riser to riser, are easily made due to the integral seal. Simply push home the respective riser until fully located.

The Shallow Access cover and frame has airtight seals which can be incorporated within the curtilage of a building.

A square top ensures the lid can easily be incorporated in paving and tarmac.

Again, jointing to the riser is easy, simply by pushing home within the respective riser.

It is recommended that all seals are lubricated prior to installation.

FIGURE 9 SHALLOW ACCESS CHAMBER 280MM


This base has been designed with a dropped main channel to eliminate possible blockages, has integral feet to ease installation, is totally airtight so can be installed internally and yet remains very cost effective.

• Square lid for easy incorporation in paving and tarmac. An airtight lid seal allows the unit to be used internally.
• Two sectional risers give a maximum invert depth of 600mm. Assembly is simple with the new ring sealing system.
• The base is supplied with secure bungs that are easily removed for pipe insertion.
• All joints feature secure rubber ring seals to give trouble free watertight joints on site.