Flow rates vary depending on the type of waste outlet and the head of water over the waste. The configuration of the discharge pipework will also have some effect. However, McAlpine 50mm water seal shower traps have flow rates varying from 20 to 50 litres per minute with a 15mm head of water over the waste outlet and when tested under controlled conditions. All traps meet the minimum requirements of BS EN 274-2:2002. Specific flow rates can be viewed on each product.