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formaldehyde probe, meter, Monitor

DirectSenseII Formaldehyde Meter

Formaldehyde (HCHO) Measurement with GrayWolf’s DirectSense II Probes

Spot-checking or continuous monitoring (updated at 1-minute intervals). Utilize GrayWolf’s newest purpose-built, rugged AdvancedSense XM meter, a Windows/Android/iOS device, and/or GrayWolfLive in the cloud to data log and access your readings.

Formaldehyde, CH2O smart sensor

Formaldehyde, CH2O smart sensor

The SEN-SMT-HCHO-L smart DirectSense II Formaldehyde sensor is ideal for the low (0 to 1000ppb) IAQ range, with an excellent L.O.D. (<10ppb). Unlike most EC HCHO sensors, this sensor exhibits negligible CO cross-sensitivity <10ppm CO (GrayWolf meters alert when >10ppm CO might influence readings whenever a CO sensor is also installed in the DSII probe).

Formaldehyde (HCHO) Measurement to very low levels of detection

The FP-31G formaldehyde meter, for portable 15 or 30 minute test results, has a range from 10ppb (parts per billion) to 1000ppb, with actual limits of detection down to <5ppb (below the display value). Display your readings in ppm HCHO. These very low levels of detection are essential for Indoor Air Quality (IAQ) measurement of Formaldehyde, and are typically not achieved by alternative continuous measurement technology.

Formaldehyde Meter


FP-31G formaldehyde meter is a portable, portable formaldehyde (HCHO) meter available from GrayWolf. Tests run in as little as 15 minutes for the higher 0.01 to 1.00 ppm range, yet only 30 minutes for the lower 0.005 to 0.400ppm IAQ range. 

Some key facts about this meter:


  • There are no known interfering gases (a significant problem for most other HCHO sensor technologies at low ppb levels).
  • Built-in sample draw pump.
  • There is no warm-up time necessary for the FP-31G, improving efficiency on-site.
  • Insertion and removal of detection (test) tablets is quick and simple.
  • Displayed readings may be manually entered onto a GrayWolf AdvancedSense meter or WolfSense LAP enabled tablet, at the time they are taken, adding those data points to any other parameters being trend logged on the other devices.
  • The FP-31G can also be used as an independent, simple data-logger, storing up to 99 readings. Logged data may be downloaded to complimentary software via an optional cable (USB-IRdA).

Photoelectric Photometry

An inserted test tablet employs the chemical reaction between formaldehyde and a chemical impregnated in the surface of the tablet. The discoloring that results from this reaction is measured via photoelectric photometry with accurate readings to <20ppb HCHO, without significant cross-sensitivity from typical background compounds, making it ideal for IAQ applications, as well as for low toxic exposure levels.

The FP-31G is easily handheld and comes with a mounting bracket for tripods (or simply lays flat) during test periods


The FP-31G stores up to 99 readings for review on the LCD display or to download to a PC

Use the FP-31G side-by-side with GrayWolf’s DirectSense II probes and other GrayWolf products 

Manually enter FP-31G measurements, at the time they are taken, together with other parameters from any compatible GrayWolf platform


GrayWolf DSII Brochure
AdvancedSenseXM Environmental test Meter
Formaldehyde Meter

Application Notes

Download “Formaldehyde Testing for IAQ Applications”
Download “USGBC Leed v4 EQc4 – Air Quality Assessment”
Download “The WELL Building Standard v1, for Air Quality Screening”
Download “Asthma Trigger Application Note”

For Detailed Information: