OSM experienced

The rules

New users of OSM may wonder what legislation and regulations are applicable to these innovative forms of construction. In their simplest forms modern methods of construction need to comply with all legislation applicable to traditional building – that is, the Building Regulations. The onus, as always, is on the developer or builder (or its design team) to substantiate that the construction is compliant.

However, even the careful design team can be caught out by the fact that OSM products and systems can use non-traditional materials or manufacturing methods. This means that consultants will not necessarily be able to point to tried-and-tested specifications and relevant British Standards as they would for traditional build.

This is where partnership with specialist manufacturers is critical. Reputable manufacturers will resolve these issues before bringing their product to the market, and will have the documentation to show compliance with the regulations.

Unfortunately, this is not as easy as it sounds either. One problem for manufacturers is that, unlike more traditional materials and components, there are often no formal national or European standards with which to declare compliance – due to standards authorities understandably lagging behind product development.

The manufacturer therefore needs to consider other means of demonstrating compliance. Possibly the best way of doing this is to have appropriate third-party approval in place for the new product, covering all the applications in which the manufacturer plan to use it.

It is important for the design team to check the validity of any certification used. Third-party approval organisations have strict review periods and certificates can lapse over time. It is also critical that the scope of the approval covers the application planned by the project team. If it doesn’t, it can mean that the assurance normally provided by the approval is not valid.

Where aspects of its product meet a particular recognised standard, the manufacturer should identify this, including the method they used to declare compliance.

An added dimension is the forthcoming European Technical Assessment Guidelines (www.eota.be) . The timber frame industry already has ETAG 007, which provides common guidance for all the European approval organisations in undertaking third-party assessments of timber frame kits. Compliance with this standard through one of the recognised European approval organisations will mean that a manufacturer can attach a CE mark to its products. Work is under way to produce similar ETAGs for volumetric buildings and steel and concrete frame building kits.