Frequently Asked Questions

What is the difference between a Penstock Valve and a Pollution Control Valve?

Penstock Valve is a very generic term used 10 years ago.  If you read the latest guidance from CIRIA 736, there is no mention of a Penstock Valve.  The common name is now Pollution Containment Valve, Pollution Containment Devices, or Pollution Control Valve.

What does a pollution containment valve / pollution control valve do?

Our pollution control valve, the Flapstopper, stops the flow entirely so it cannot carry on down the pipework.

What is the difference between the Flapstopper and Flapstopper Box Valve?

The Box Valve version of the firewater & pollution containment FlapstopperTM is a revolutionary solution that overcomes the issues associated with opening a firewater & pollution containment Flapvalve under water pressure, as well as provides access for inspection and servicing.

What is CIRIA c736?

This guide is an update to CIRIA R164 Design of containment systems for the prevention of water pollution from industrial incidents published in 1997, and has been developed to assist owners and operators of industrial and commercial facilities storing substances (inventories) that may be hazardous to the environment.


It provides guidance on identifying the hazards, assessing the risks, and mitigating the potential consequences of a failure of the primary storage facility and/or the combustion of its contents.  A 3 tier risk assessment methodology is introduced with recommendations for different ‘classes’ of construction for each.


It is applicable to the containment of a wide range of inventories and to all sites from small commercial premises with a single storage tank, to large chemical or petrochemical sites.  It also applies to warehouses storing hazardous inventories.


Information is provided on the design, and construction of new secondary containment systems and also the inspection, maintenance, repair, extension, and upgrading of existing installations.

What is the Environment Agency's PPG18 Guidance?

These guidance notes have been drawn up to assist in the identification of the equipment and techniques available to prevent and mitigate damage to the water environment caused by fires and major spillages.


They are jointly produced by the Environment Agency for England and Wales, the Scottish Environment Protection Agency (SEPA), and the Environment and Heritage Service for Northern Ireland, referred to as the Agency or Agencies.

What is Firewater and how can I contain it on site?

Firewater is a cocktail of potentially very flammable chemicals on site, which in the event of a fire can melt down and / or set a light extremely quickly, for example in a waste recycling plant.


When hazardous material becomes a liquid and escapes from a building, it’s going to enter the normal drainage systems, ultimately contaminating local streams, rivers and the ocean which is a criminal offense.




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