Details
 

Researcher:	Stephen Ledbetter Henk De Bleecker
Funded:	DETR 50%, industry 50%
Total value:	£28,500
Lead partner:	CWCT
Status:	Completed

Background and justification:

The technology of fenestration and facades has evolved over many years but recent changes have been rapid and significant. There are now forms of facade construction for which there are no directly relevant standards or guidance. A widespread practice has developed whereby the standard that most closely matches the requirements of the wall is 'adapted', often mistakenly, to do the job.

Glazing frames where traditionally face sealed by embedment of glass in a mastic sealant with no need to keep the edge of the glazing dry. Todays glazing systems are sealed by gaskets and weatherstripping with a cavity between the inner and outer seals. The cavity is drained, drained and ventilated or pressure equalised yet current standards do not fully account for this behaviour which significantly affects the durability of both glazing and frame. Whereas some countries have a single standard for all types of window the UK has standards specific to the framing materials of wood, steel, aluminium and PVC-u. Increasingly window frames are made as composites of more than one material to improve durability and termal performance and there are no standards directly relevant to such windows.

Facades where traditionally either single face sealed skins or heavy constructions that absorbed water. Modern curtain walling may be a face sealed single skin but normally takes the form of rainscreen or glazing frames with a double line of defence. This concept of creating a multi-layer wall with separate sealing against air leakage and water penetration offers advantages in terms of: ease of construction, economy of construction, thermal performance, risk of water penetration and maintenance. Yet there are no UK standards applicable to multi-layer or rainscreen walls and no work within CEN to create such a standard. The work of CEN TC33 relates only to glazing screens.

BS8200 has been the definitive document on non load-bearing walls for two decades. BS8200 is still refered to by the Building Regulations yet it has not been maintained and the industry now agrees that it is not relevant to todays non-loadbearing walls. This work will identify those standards that are relevant today and those need to replace BS8200 or support its replacement.
 

Objectives:

Identify all those UK and EU standards and guides that relate to the performance of fenestration and building facades.

Categorise all current methods of construction for fenestration and facades and future trends.

Identify all duplication of standards, conflict of standards, and need for new or improved standards.
 

Outputs: