What is the difference between Sample Draw and Diffusion-type gas monitors?

The specific environment you are working in will determine if you need a Sample Draw or Diffusion-type gas monitor.

The main difference between the two is the way it samples for gases. Sample Draw monitors use an internal motorized suction pump. This enables the operator to draw and sample areas from a safe distance using a sample hose, to verify that conditions are safe before entering. Diffusion monitors are passive devices that sample wherever the detector is located, and require the operator to be physically in the area where gas is potentially present.

The other difference that you may encounter between the two types are cost and size.

Sample Draw monitors are generally higher priced due to the cost of the pump.

Diffusion instruments are smaller, lighter, quieter, and considerably less expensive. Many Diffusion instruments also have an attachable sample drawing pump available as an optional accessory.

In summary, Diffusion instruments are commonly used for personal monitoring and personal safety, while Sample Draw instruments are used when performing remote monitoring.

Find more information about RKI portable gas detectors here.

This article provided by RKI Instruments, Inc. –  View or download the PDF file here.