There is a worldwide growing demand for polystyrene latex sphere particles (PSL) by filter manufacturers, end-users and third-party testing services. PSL spheres are listed as suitable test materials when using particle counters by both the Institute of Environmental Sciences (IEST) and European Norm (EN) standards. HEPA-CHECK Filter Challenge Particles are polystyrene latex particles optimized for performance, aerosolization, safety and economy for both HEPA and ULPA filter testing. Unlike traditional oil-based filter test materials such as DOP, called dioctylphthalate, the HEPA-CHECK PSL sphres do not have carcinogenic health risks associated with atomized oils such as dioctylphthalate or other oil-based filter test materials. Due to the clean, oil-free nature of this ultra-pure water suspension, HEPA-CHECK is ideal for leak testing in-situ filters where the highest degree of cleanliness is required. Our polystyrene microspheres, for HEPA and ULPA filter testing, are manufactured with a consistent, repeatable supply of highly uniform, monodisperse PSL particles that meet or exceed efficiency filter test requirements.
Each 25 mL bottle is to be diluted in one US gallon (3.79 liters) of clean water and then nebulized. Nebulizing can be accomplished by using commercially available ultrasonic PSL Generators, such as a High Output PSL Generator. Single use bottles ensure reproducible test conditions from site to site. The product is available in particle sizes from 0.12um to 0.3um, sizes normally associated with testing mean particle penetration size, MPPS, and is sold individually or in convenient packs of 6 or 20 bottles.
Polystyrene Latex, PSL Spheres
Index of Refraction
1.59 @ 589nm (25°C)
7.5 x 1012 /mL
Polystyrene microspheres in Dionized water
Trace amounts of surfactant to inhibit agglomeration and promote stability
≤ 24 months
Bottle Size and Volume
A: 25ml, 1 Bottle (Off the Shelf), B: 25ml, 6 Bottles (Off the Shelf) C: 25ml, 24 Bottles