ADCAS moves to rationalise sizes of air terminals

Paul Adlam
Paul Adlam, president of ADCAS, surveys just a few of the one million grille and diffuser options that the association is working to rationalise.
An initiative to boost productivity and reduce costs in the market for air terminal devices launched by the Association of Ductwork Contractors & Allied Services (ADCAS) is aimed at rationalising the enormous range of sizes and variations that are used. Delegates to a recent ADCAS meeting heard that as many as a million different sizes of diffuser, grille and plenum could be required if specifiers continue to order variations of just 1 mm in height and/or width. ADCAS president Paul Adlam said, ‘This overkill situation precludes any meaningful stocking by manufacturers and generates huge inefficiency at every level, from design office to site.’ To tackle the problems ADCAS has teamed up with the HEVAC Association in a drive to rationalise the sizing of air terminal devices. ‘The potential benefits,’ explains Mr Adlam, ‘are enormous in terms of more efficient production and stocking policies, easier installation and cost cutting at every level — which should mean higher profits for all concerned.’ The initiative is endorsed by HVCA, BSRIA and FETA and has already examined standards of good practice. Leading manufacturers were asked to submit details of the most frequently requested product sizes , and a list of rationalised sizes has been compiled for grilles, diffusers and plena. Recommended standard heights for grilles are from 100 to 600 mm in 50 mm increments and 600 to 1200 mm in 100 mm increments. Linear bar grilles should be available in standard heights of 100, 150, 200, 250, 300, 400, 500 and 600 mm, with lengths varying as required. Square, circular and linear diffusers are normally provided with a plenum box for final connection to the ductwork system. The recommendation is for spigots with the following diameters: 63, 80, 100, 125, 160, 200, 250, 315, 400 and 500 mm.
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