Secondary filters
Illustrated Guide to Ventilation (BG 2/2009), compiled by Kevin Pennycook and published by BSRIA in 2009, states: ‘Secondary filters (classes F5 to F9) have an average efficiency ranging from 40 – 95%. Average efficiency is defined at the weighted average of the efficiencies for the different specified dust loading levels up to final pressure drop. The air velocity through the filter media is typically 0·02 – 0·1 m/s. Secondary filters are effective in trapping pollen, bacteria and dust. Secondary filters can be of the extended media bag type, pocket type or a rigid bag.’
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
Combining mid-career qualifications with experience broadens career opportunities.
Why being a mentor can help your career.
Channel 4 broadcaster to host 125th anniversary ceremony.
Listed structures on the rail network
Heritage interests and operational requirements must be balanced.
Historic England publishes research into embodied carbon when retrofitting traditional buildings.
New Prime Minister delivers on ECA call for cut in electricity costs.
CIOB reacts to the announcement of Andy Burnham as Prime Minister.
Heritage and conservation science workforce survey - Have your say.
England's Suburbs 1820-2020. Book review.
New, more proportionate and targeted approach for higher-risk building assessments.
Government brings British Steel into public ownership.
UKCW Birmingham returns with bold new theme and focus.