Drain plug is used to temporarily block a drainage pipe whilst testing is carried out.
Centre locking drain test plugs with plastic blanking cap, suitable for air or water testing of drains and sewers.
Screw type pipe stoppers are widely used for water and air testing pipes, drains and sewers. Screw type stoppers are also used for unwanted entry into the pipeline and also be used as a temporary seal for new pipes, drains and sewers during maintenance on construction sites.
Water and Air Testing of Drains and Sewers
Testing of drains and sewers is governed by the requirements of BS8301: 1985, the Code of Practice for Building Drainage and BS8005: 1987, the British Standard for Sewerage. Similar requirements are also stated in Water Authorities Association publications.
Additionally these test plugs enable compliance for testing of drains and sewers in accordance with European Standard EN 1610: 1997.
General Procedure for Air & Water Tests
The following procedure should be adopted prior to testing.
- Inspect the pipeline for possible damage sustained during or subsequent to laying.
- Clear the pipeline of any debris and flush out.
- Check that all pipe joints have been correctly made.
- If any cement mortar joints have been used, leave for at least 24 hours before testing to allow the mortar to set and reach adequate strength.
- Thoroughly check all plugs and equipment. Make sure that any rubber tubing used in connections is in good condition and not perished.
- Fit expanding plugs into the ends of the pipeline and all branches. Make sure that the surface of the pipes where plugs fit is also clean and free from any extraneous material such as grit.
N.B. Concrete pipes may require the installation point areas cleaned of any irregular surfaces to ensure a good seal. If necessary, due to some concrete surfaces being porous, the area should be painted to create a good seal.
- 1-inch (25.4mm) head of water gauge is equivalent to 0.036Ib. per square inch.
- 1ft. head of water is equivalent to 0.432Ib. per square inch.
- 1Ib. per square inch is equivalent to 2.3ft head of water.
- 1 bar is equivalent to 14.7Ib. per square inch.
- 1 bar is equivalent to 33.35ft. head of water.
Air Test - Testing Procedure
- Seal pipe section with appropriate size drain test plug.
- Fit test nipple to one of the drain test plugs.
- Connect rubber hose via ‘Y’ piece to nipple, ‘U’ gauge and hand bellows.
- Fill ‘U’ gauge with water to ‘zero’.
- Squeeze the handle bellows gently until the level reaches 100mm on the open side of the gauge and the lower limit below zero on the closed side. The level should not fall to less than 75mm during a period of 5 minutes without further pumping, after allowing a suitable time for stabilization of air temperature. If it drops below 75mm within the specified time the pipe section is leaking.
Water Test - Testing Procedure
- Fit an expanding plug, suitably strutted to resist the full hydrostatic head, at the lower end of the pipeline. Also plug any branches. The pipes may need strutting to prevent movement.
- Provide a means of applying the test head of water at the top end of the line, preferably using a 90° bend and a straight pipe of the same diameter as the line. Ensure that the standpipe and plug are suitably strutted to resist the applied hydrostatic head. Provide a means of filling the pipeline with water.
- Fill the system with water keeping pockets of trapped air to a minimum.
- Fill the standpipe to the requisite level.
- Leave for at least two hours to enable the pipes to become saturated, topping up as necessary.
- After the absorption period measure the loss of water from the system by noting the amount needed to maintain the level in the standpipe over a further period of 30 minutes. In carrying out the test to the requirements of BS8005, the standpipe should be topped up at regular intervals of 5 minutes and the amounts measured.