37. A public body may require a quality assurance system, including the ISO 9001: 2000 standard, or a specification relating to sustainable development and the environment for the carrying out of a contract. The public body must specify the requirement in the tender documents.
If such a requirement unduly reduces competition, the public body must allow any supplier to submit a tender and grant to a supplier that fulfils the requirement referred to in the first paragraph a preferential margin not exceeding 10%. In the latter case, the price submitted by such a supplier is, for the sole purpose of determining the successful tenderer, reduced by the preferential margin, without any effect on the price for contract awarding purposes.
The percentage of the preferential margin to be applied must be indicated in the tender documents.