The HIAC liquid particle counting HRLD series of light obscuration sensors are the industry leaders in reliability with a wide range of flow rates, high concentration limits and wide dynamic range.  HIAC HRLD sensors can be used in both on-line and batch operation, and are highly adaptable for nearly any application.

Liquid Particle Counting | Benefits of selecting the HIAC HRLD series

HIAC Reliability

Count repeatability better than 5%, which exceeds ISO 11171 particle counting calibration standards as well as NIST traceability calibration

Manage all your applications for any fluid and reporting standards

Test aqueous solutions as well as oils and caustic fluids on one instrument. Supports ISO 4406, NAS 1638 and user-defined tests to ISO MTD, ACFTD, and ISO 11171 particle counting standards Particle counts from 1.2um to 600um enabled with interchangeable sensors

HIAC global service

The HIAC HRLD is a workhorse! With over 25 years of field use coupled with unrivaled industry support and service, the HIAC HRLD is an industry standard

HRLD Series Model Number Measurement Range (μm) Concentration Limit <10% coincidence) Flow Rates (mL/min)
HRLD-100 4 μm(c)-100 μm(c)* 10,000 20-100
HRLD-100HC 4 μm(c)-100 μm(c)* 18,000 10-50
HRLD-150 1.3 min.-150 18,000 10-25
HRLD-150JA 1.3 min.-150 18,000 10-25
HRLD-400 2.0 min.-400 10,000 20-100
HRLD-400HC 2.0 min.-400 18,000 10-50
HRLD-600JS 2.0 min.-600 6,000 30-200
* As per ISO 11171 and ISO 4406, note that 4 μm(c) < 2 μm
Pressure Limit 69 bar (1000 psi)
Sample Temperature Limit 65°C (150°F)
Calibration Options ASTM F658-87 (PSL spheres); ISO 4402 (ACFTD in oil); or ISO 11171 (MTD in oil). For pharmaceutical applications, sensor resolution can be factory tested in accordance with USP <788>.
When ordering, specify HRLD-100 or HRLD-100HC HRLD-150 or HRLD-150JA HRLD-400 or HRLD-400HC HRLD-600JS
Compliance Certifications CE Compliant per EMC and Low Voltage Directives Class 1 Laser Product Complies with IEC/EN 60825-1 and 21 CFR 1040.10 pursuant to Laser Notice 50

Examples of common fluids used by HIAC customers with HRLD series liquid particle counting sensors include:

HRLD series 100, 150, 400:

Hydraulic fluids

Phosphate esters

Water for injection

Common solvents


Diesel fuel

Jet fuel (JP4, JP5, and many others)

Purified water


HRLD series 150JA and 600JS are commonly used with:





Sodium hydroxide

Hydrogen peroxide

Ammonium hydroxide

*Viton™ seals standard. Kalrez™ seals available for phosphate esters