To ask the Secretary of State for the Environment if the new BSI specification for sewer pipes will ensure that all concrete, clay or plastic pipes will include a 100-year life expectancy. [34515]

Many factors affect the life span of pipes. These include pipeline design, pipe handling and laying and subsequent ground movement. It is not therefore possible to ensure any particular life expectancy.

To ask the Secretary of State for the Environment what assessment he has made of the adequacy of twin-walled plastic tubing as a material for the construction of sewer pipes; and if he will make a statement. [34517]

This is a matter for water and sewerage undertakers.

To ask the Secretary of State for the Environment if the new BSI specification for sewer pipes will guarantee a strength which will withstand a jetting pressure of (a) 2,500 or (b) 10,000 psi. [34516]

This is a matter for the BSI. I cannot comment on a specification which is still under development.

To ask the Secretary of State for the Environment up to what psi pressure jetting contractors operate in the removal of obstructions from sewer pipes. [34514]

This is a matter for the contractors. Guidance is being developed within industry on the use of water jetting for cleaning sewers, which will cover a number of factors such as pressure losses in transmission and the design and control of the nozzle as well as the pressure developed at the pump.