"Measuring moisture content, one of the 7 main criteria"

Philippe JARIEL, General Secretary and Technical Director of UNRST-FFB, is the brain behind the update to the French regulation that came into force on 5 April 2007.
The regulation (DTU 53.2 - reference AFNOR DTU P 62-203) has been in force since October 1990 and its aim is to set out the framework for installing PVC floor coatings (choice and installation techniques).

A method to assess a substrate

"Through my different activities, my main objective is to promote, defend and highlight the job of those involved in floor coatings within the trade union, UNRST. This trade union includes 2,200 member companies from the network of the French Construction Federation, a total of some 40,000 employees. I believe that the construction industry must be based on quality; this is why it was necessary to completely revise and reform this regulation; its last version dated back to 1990”, explained Philippe Jariel.
"The initial assumption was to introduce a method for a contractor to ‘assess a substrate’ before embarking on installing a floor coating. This method, which is a complete analysis consisting of 7 key points, is the result of the various tests conducted. The analysis is then formalised in a report, signed by the parties involved. The report is binding and can be useful in the event of a dispute."

Measuring moisture content in substrates

"We have designed a non destructive, fast and modern method for measuring the moisture level in hydraulic substrates. Measuring the level of moisture is one of the 7 most important criteria of this regulation for analysing substrates. In collaboration with CSTB, we set out a standard method for measuring humidity contents, “HRE”, which is non destructive, fast and modern.
It was tested in the laboratory and on site throughout France for 3 years. The new “ERH” measurement standard complements the method for measuring the weight of water in a substrate using the carbon carbide method, which is destructive and requires a sample of the substrate to be taken. This new method measures the humidity of the suhstrate in relation to the humidity of the atmosphere where the substrate is situated, i.e., the Equilibrium Relative Humidity, which is assessed using a humidity-sensitive probe.

"Before a PVC floor coating to be stuck under this regulation, the equilibrium relative humidity, “ERH”, must be less than or equal to 85%. If it is over 85%, the contractor can chose to do one of the following:
- wait for the substrate to reach the acceptable level by letting it dry completely,
- verify the results using the carbon carbide method,
- propose an alternative technical solution to the client."
These measures help you rationalise your technical choice of method for installing stuck PVC floor coating and ensure proper application, in compliance with the new regulatory standards.

I could say much more but, in conclusion, I would suggest that contractors increased mechanisation and by so-doing, acquired all the necessary tools for assessing substrates, including an “ERH” Hygrostick Probe such as the Humitest MMS with sleeves. This is currently the best instrument for assessing moisture contents in hydraulic bond-based substrates”, concludes Philippe Jariel.

Business
The National Union for Technical Floor Coatings of the French Construction Federation (UNRST-FFB) works with 2,200 companies on three main points:
-Research and development in the field of floor coating installations,
-Setting standards and drafting regulation,
-Initial and on-going training.