The Dri-Eaz HEPA 500 DOP Pre-Filter makes the DefendAir HEPA 500 a high-efficiency three-stage air filtration unit, ready for any sensitive job requiring first-pass HEPA filtration. With the standard pre-filter, DOP Stage 2 pre-filter and the HEPA primary filter installed, the HEPA 500 passes laboratory DOP testing conducted per ANSI standards, achieving an efficiency rating of 99.97% against oily aerosol particles down to 0.3 microns.

DOP stands for "Dispersed Oil Particulate," the name of a standard procedure for testing the effectiveness of HEPA filtration. The DOP test introduces a dense cloud of extremely fine particulates into the filter under controlled conditions. DOP testing is often conducted on specific types of stringent air-quality control job sites that require first-pass HEPA filtration.

Features:

Passes laboratory DOP testing when installed as part of a three-stage filtration process
Equips the HEPA 500 for a wide range of environments that require first-pass high efficiency air filtration.
Install the DOP filter between the standard pre-filter and the HEPA primary filter.

The Defendair HEPA 500 can be configured with a variety of filters to suit your specific air scrubbing requirements. Use the chart below to find the best filtering configuration for the job at hand.

Filtering Application	First filter position	Second filter position	Final filter (HEPA)
Clean water loss air scrubbing. For a relatively clean environment.	(no filter necessary)	2nd Stage Pre-Filter (F271 or AC36F2)	HEPA filter (F321)
Standard air scrubbing. For environments with higher particle loads, such as construction or remodelling sites.	1st Stage Pre-Filter (F270)	2nd Stage Pre-Filter (F271 or AC36F2)	HEPA filter (F321)
First pass efficiency air filtration. For use with a negative air setup during remediation of high-risk contaminants and/or when DOP testing is required.	(no filter necessary)	DOP Pre-Filter (F415)	HEPA filter (F321)
Odour control and air filtration. For the removal of volatile organic compounds (VOCs), food odours, fumes from paint and paint thinners, sewer odours, and many other noxious odours.	Activated Carbon Filter (F397)	2nd Stage Pre-Filter (F271 or AC36F2)	HEPA filter (F321)

Filter Types:

1st Stage Pre-Filter (F270). Synthetic fibre filter media rated at 10% efficiency. Captures the largest particles to help extend the life of the higher efficiency filters inside—more info.
2nd Stage Pre-Filter (F271 or AC36F2). Synthetic fibre filter media rated at 30% efficiency. Captures larger particles to help extend the life of the HEPA filter—more info.
DOP Stage 2 Pre-Filter (F415). Use of the DOP filter ensures laboratory-grade performance for sensitive jobs that require first-pass HEPA filtration—more info.
Activated Carbon Filter (F397). The activated carbon filter removes a wide variety of compounds, including volatile organic compounds (VOCs), food odours, fumes from paint and paint thinners, sewer odours, and many other noxious odours. Combining activated carbon filtration with HEPA filtration is especially effective in removing airborne soot particles and the odours they create. More info
HEPA filter (F321). The HEPA filter has an efficiency rating of 99.97% against 0.3 micron oily aerosol particles. The HEPA filtration standard was developed in the 1940s to control radioactive dust particles in U.S. nuclear laboratories—more info.