Primary filters
Illustrated Guide to Ventilation (BG 2/2009), compiled by Kevin Pennycook and published by BSRIA in 2009, states : ‘Primary filters (Grade G1 to G4) have an average arrestance ranging from 50 – 90%. Average arrestance is the amount of dust retained as a percentage of the total load (a ratio). Primary filters can arrest particles down to 5 um but have a minimal effect on particles below 1 μm. Air velocity through primary filters is an average of 2 m/s, and the pressure drop rises from 10-60 Pa when clean to 125-250 Pa when dirty. These filters can be permanent and cleanable (made of foam or metal mesh) or disposable (made of a glass or synthetic media). Primary filters are mainly used to protect ventilation and air conditioning equipment (if building use does not require filtered air), or as pre-filters to extend the operating life of fine filters installed further downstream.’
--BSRIA
[edit] Related articles on Designing Buildings
Featured articles and news
Top 50 firms awarded 52bn of projects in the last year
New engineering data shows.
Enhancing construction site reporting efficiency
Through digitisation and the digital revolution.
Noise in the built environment
BSRIA guide TG 20/2021.
17,000 people suffer conditions as a result of exposure to excessive noise at work.
Turning down the noise: Auditory health
A pervasive risk with far-reaching consequences.
UK Construction Week, London is here !
Debuting major international pavilions and much more.
Getting the most out of heat pumps and heating
How heat pumps work and how they work best.
Plumbing and heating for successful retrofit and renovation
Low temperature underfloor systems and heat pumps.
Cost-of-living crisis and home improvement plans
Starting on the right footing and top tips for projects.
Delays on construction projects
Types, mitigation and the acceleration of works.
From Chaucer to Fawlty Towers.
Electrotechnical excellence, now open for entries.
Net zero electricity grids BSRIA guide NZG 5/2024
Outlining the changes needed to transition to net zero.
CIOB Global Student Challenge 2024
Universitas Indonesia wins for second year running.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.