Oxford Method Research Programme

The Regional Estates Department decided when developing 6M from the lessons learnt in 3M, that the engineering services should be developed as part of the building system. Features such a consistent structure where the “A”s and “V”s in the structural lattice were consistent throughout the length of a building, a twin boomed beam and a profiled decking on the structural soffit arose from the team development. The consistent “A”s and “V”s providing a predictable size and a continuous route for ductwork and drainage. The twin boomed beam provided for service drops even at beam locations. The profiled decking provided easy, fast and consistent support for engineering services.

In addition to the building structure incorporating servicing features, a discipline was developed to predict service locations to aid design teams co-ordination, construction speed and known maintenance requirements.

The drawings have been selected for inclusion on this web page to illustrate features which will hopefully be of use to building managers.

The following notes may help explain some elements of the drawings.

04041/6M/E01

• Luminaire locations were selected to centre luminaires on ceiling tiles.
• Fixing centres were selected as 750 rather than 600 to avoid a clash with the ceiling tile support grid.
• Luminaires were advised to be installed as surface to provide a more economic lighting solution as the ceiling offered a very high reflection factor and the resulting scheme provided a “brighter” environment. As a secondary issue, no satisfactory solution was then available for fire rating the spine of recessed luminaires.

04041/6M/E02

• A support channel was developed with ceiling contractors to support luminaires, switch boxes and conduit boxes on the ceiling.

04041/6M/E03

• It is interesting the 1150 height for light switches and mid height socket outlets in 6M still complies with the latest Building Regulations (2004).
  

04041/6M/M01,  04041/6M/M02 and 04041/6M/M05

• The majority of 6M projects have circular spirally wound ductwork to get the maximum air volume through the lattice structure and to facilitate faster installation on site. All supply and extract grilles were selected as 4 way throw units to provide a consistent appearance. Supply grille quadrants were blanked off as necessary to provide the required throw.
• A system was developed with the grille company, Royaire and Burgess Ceilings to provide a detail for installing supply and extract diffusers in a ceiling and maintaining the ceilings one hour fire rating. The mineral wool wrap and the requirement to continue it for 2000mm along the flexible duct connection is an essential part of maintaining the fire integrity. The components for this detail are still in manufacture.
• The plenum box with integral damper was added to the 6M system to meet the requirement of the HTM concept of hazard rooms, when it was introduced.

04041/6M/M04 and 04041/6M/M06

• These details came from tests on service penetrations in fire compartments in other building constructions and were adapted for 6M.

General Engineering Notes for 3M and 6M

• 3M buildings were often wired in mineral insulated metal sheathed cable (MIMS). For a period when copper prices were high, an aluminium sheath mineral insulated cable was used which has proved to go brittle with age.
• Services in 6M buildings were run orthogonally to help with maintenance. (Post contract data cable installers often ignored this principle).
• The electrical wiring in 6M generally relied on trunking and conduit to provide the earth. This was common in building construction up to this time.

M. Crowther
Couch Perry and Wilkes Partnership