Custom HEPA Filter Manufacturing, Testing & Certification

APC Filtration

APC Filtration’s test lab


May/June 2015 | Volume 34 No. 3

Original equipment manufacturers (OEM) that require critical air (HEPA & ULPA) filters for specialized equipment often find that standard size or “off-the shelf” filters do not provide the level of filtration performance, filter life, installation and/or removal that they require. Specialized equipment OEMs often require a HEPA filter designed specifically for their piece of equipment to provide an optimum and measurable level of filtration, pressure drop and service life to provide an optimal level of equipment performance within the environment the equipment is subject to.

HEPA Filters – Equipment & Application Design

APC Filtration Inc. is an ISO 9001:2008 certified manufacturer providing over 34 years of experience in custom air filter design, engineering, manufacturing and filter testing for a very diverse and global range of OEM industries and applications.

APC’s RFQ (request for quote) process has advanced over the years and is now capable of providing pricing and rapid prototype filter (RPF) samples within 2-3 weeks. In specific cases, RFQ’s have been signed off and RPFs manufactured within 72 hours. The purpose of the RFQ process is to obtain all product specifications and performance requirements up front to avoid costly mistakes and increased timelines that may delay the OEM equipment introduction to their market or client base. Once all parties sign off the RFQ, a simplified filter development initiative is summarized below:

Filter Design:
APC engineers designed an air filter-modeling program for use with AutoCAD and SolidWords to produce 3D fluid dynamic imaging to help determine optimum filter design and performance efficiencies.

Rapid Prototyping:
From the filter design phase, CAD files are sent to a 3D printer that produces prototype filter parts for filter assembly, test fitting and filtration performance testing in a lab environment or real world environment. This is an essential step in their filter design process when timelines are critical.

Lab Testing:
APC lab technicians perform a variety of filter tests to verify that filter design, function and performance meet all RFQ requirements. Tests performed may include air filter leak testing, fractional efficiency (FE) filter testing and air filter certification to North American or European test standards.

In cases where clients submit their equipment for filter design and fitment testing, the equipment is integrity tested to ensure a positive filter seal and no exhaust air leaks are present in the equipment housing. Equipment integrity testing insures the custom HEPA filter and their client’s equipment meets the air filtration standard and integrity for their application. This process significantly reduces new product launch timelines.

Field Testing:
If equipment field-testing is required vs. lab testing, prototype and/or pre-production QC filter testing is required to obtain filter production approvals. This is a lengthier process to achieve filter design approvals prior to production. However field-testing allows clients to perform real world testing in various environmental conditions that cannot be duplicated in a lab environment. Typical industry segments that require field-testing approvals include:

  • Aerospace
  • Agricultural
  • Air Purification
  • Appliances
  • Automotive Equipment
  • Biological Equipment
  • Cabin Air Filters
  • Containment Systems
  • Dental Equipment
  • Disaster Recovery Ventilation Equipment
  • HVAC Equipment
  • Infection Isolation Rooms & Surgical Suites
  • Manufacturing Equipment
  • Mobile Equipment
  • Medical Appliances & Equipment
  • Off-Road Equipment
  • Pharmaceutical Equipment
  • Protective Environment Rooms

HEPA filters are capable of capturing sub-micron particles down to 99.995% at 0.3 m from the air however; they do not adsorb odors, gases or VOC’s. Capturing these elements requires the use of GAC (granular activated carbon) and may require other additives. The following projects are not specific to HEPA filtration or odor adsorption; however they represent a small cross section of industry and air filter applications.

Military Vehicles – Cabin Air Filtration

Crew cleaning an air filter from equipment at a wildfire site.

Crew cleaning an air filter from equipment at a wildfire site.

BAE Systems is a global defense, aerospace and security company employing approximately 88,200 people worldwide. Their wide-ranging products and services cover air, land and naval forces, as well as advanced electronics, security, information technology and support services. In 2013, APC was contracted to design, test and manufacture a custom designed cabin air filter to keep critical military equipment running efficiently and reliably in the most demanding environments. APC’s in-house testing lab provided the capabilities to fully test and support the broad range of testing requirements required to thoroughly analyze filtration performance and filter certifications. Rapid prototypes filter manufacturing and filter media selection allowed APC to develop and test filters with custom filter media selections quickly and efficiently, reducing product development timelines. APC played a critical role for their client to develop a proven functional filtration solution for extreme environments. Their filters have been used worldwide in the roughest military applications, proficiently filtering cabin air as well as reducing noise. A critical job of the military and its equipment is to deliver tactical supplies, equipment and troops in any weather, environmental and operating condition.

Food & Pharmaceutical Equipment – Aseptic Processing

Aseptic processing is the process by which a sterile (aseptic) product (typically food or pharmaceutical) is packaged in a sterile container in a way that maintains sterility. Sterility is achieved with a flash-heating process (temperature between 195 and 295┬░F (91 to 146┬░C) which retains more nutrients and uses less energy than conventional sterilization techniques. Pharmaceutical sterile processing includes use of clean rooms, bacteria retaining filters and dry or steam heat. Aseptic food preservation methods allow processed food to keep for long periods of time without preservatives, as long as they are not opened. APC was contacted by the equipment manufacturer to design a custom made HEPA filter for their aseptic processing equipment. The filter body and installation assembly was designed entirely out of 316, #4 brushed stainless steel to withstand the disinfectant cleaning cycles that use vaporized hydrogen peroxide. Custom designed packaging was designed to prevent filter damage and insure filter integrity when a client required drop shipping replacement filters to their global equipment clients.

Chemical & Biological Appliances – Bomb Shelters

Around the world there are places where homeland security consists of public and private shelters for the protection of its citizens against bombs, chemical and biological fallout. These fallout shelters come complete with modern safe room filtration technology that allows for safeguarding against chemical and biological agents. Early in 2012, APC Filtration Inc. was commissioned by a global manufacturer to design, manufacturer and test HEPA and ULPA filters for a series of chemical and biological shelters. These custom filters needed to capture and filter out various gases and particle sizes while doing so in a variety of temperature and humidity environments.

For more information about APC Filtration Inc. visit