Measuring particulates

Toxic and Carbon Dioxide Span Calibration

To perform a span calibration with a specific toxic gas, please reference the toxic gas table. For the CO2 span calibration, the range (or span) should be a sizeable fraction of the selected full scale range of the gas.

;; NOTE: The range for the CO2 sensor is 0 to 5,000 ppm. For a span calibration, it is recommended to span cal to the value you will be measuring (i.e., 2,000 ppm).

1.Connect the appropriate gas, regulator, tubing and cal cap to the EVM.

2.Follow steps 2-4 above (in Toxic Zero Calibration section) but select Span softkey in step 3. (NOTE: For Oxygen span calibration, the typical span is 20.9%.)

Logging Toxic Gases or Carbon Dioxide

1. From the Start screen or any Measurement screen, press key.

•To view gas measurements, select either the Gas or Composite screens

(by pressing from the start screen when Setup is selected.)

2.Press key to stop logging. (See “Viewing logged results” to access past sessions.)

Run Icon
CO2 value	Composite
Toxic (CO)	Measurement screen
value

Particulate advanced calibration (Gravimetric filtering)

Gravimetric Calibration Overview

(1)Reset the gravimetric and volume accumulators; (2) Insert a new (sealed) gravimetric cassette; (3) Measure in the specific location for approximately four to eight hours; (4) Notate the value displayed in the gravimetric accumulator field (displayed in the particulate screen. (This value is used in conjunction with the weight of the measured dust in the cassette.); (5) Remove the gravimetric cassette and weigh the filtered contents. (Typically, sent to a lab for results.); (6) To determine the correction factor, calculate the ratio between the particulate mass value and the weight from the gravimetric filter lab analysis.

1.	From the start screen or any measurement screen, press the		key. (Prior to
	logging, a 5 second count-down appears.)
2.	Press	key to end the logged session. (See “Viewing logged results” to view past
	sessions.)