Arkansas HVACR NewsMagazine September 2019

S tate, National, Chapter News Tech News

air flow rate through the material can vary significantly. So what is a practical velocity flow to benchmark filters by? Leading utilities in California (Pacific Gas & Electric, Southern California Edison, San Diego Gas and Electric, Southern California Gas Company) commissioned a study* to serve as a guide for air flow velocities that support efficient, effective filter performance. The study indicates 300 fpm face velocity for filter flows as a maximum. This is a far cry from the generally accepted velocity of 500 fpm most filters are rated at. Pressure drops can double at the higher velocities costing consumers comfort, noise and money in operating costs and warranty issues. Penalties- If we use one inch filters or inferior media material we must slow down the air flow well below the 300 fpm marker. When we slow down the air we require more filter surface. More filters mean more service points, possibility of higher

air delivery system. As a HVAC contractor you should assess air flow requirements and filter performance to insure adequate comfort and equipment protection on each job. We must pay attention to expected conditions within the home with regard to particulate size to assure we are making the proper choices to insure great indoor air quality. The contractor should then drive the customer to the appropriate filter market with education and /or a program for maintenance.

Installing- Instructions? We don’t need instructions! We seldom review

equipment installation instructions. The enclosed information states airflow and resulting static pressures are provided minus a filter. (Figure 1)

infiltration and excessive replacement cost. There are many other factors to deal with when selecting appropriate filtering. We set aside technical aspects of filter performance (dust spot, particulate matter and gaseous pollutants) and have focused on the physical restrictions of the