How to perform on surface RH Hood test as per BS 8201, 8203, 5325?

Careful consideration should be given to the location of the test site. The hood should not be located in direct sunlight or in an area which can be accidentally disturbed. The floor slab surface should be abraded, cleaned of any foreign materials and swept clean of any dust or loose materials that could affect a proper seal between the hood and surface of the floor. The floor should be prepared as specified in the relevant standard.

Use of artificial aids for accelerated drying of concrete is not recommended. If they are being used it is recommended that they be turned off at least 96 hours before taking final readings.

Using a double-sided preformed adhesive/butyl tape, seal the insulated RH hood to the concrete surface.

Insert Hygro-i2 probe into the hood using the insertion/ retrieval tool.

Please refer to the period of time as specified by the standard being followed for the duration of the test. The user should always refer to national standard guidelines for definitive and current procedures and specifications.

When the time period has elapsed, check that meter readings do not drift by more than 1% RH over a 5 min period. Ensure the readings correspond with the floor covering/adhesive manufacturers' or national standard recommendations before applying floor covering. e.g. British standards code of practice BS8203 suggests that a concrete floor should be sufficiently dry to allow installation of a resilient floor covering when the measured relative humidity falls to 75% or lower using the insulated impermeable box/hood method as specified in the above standard.