I had my first extended time with an industrial hygienist in an underground frac sand mine. We had installed our cab air quality test equipment in a scaler (see picture below.) and we were waiting for it to finish its shift to allow us to remove the test equipment. We stepped out of his truck, and he pulled out his flashlight and pointed it straight up. The light reflected off a sea of moving particles making it look like a solid column of marble. He then demonstrated how to measure airflow inside the mine while pointing the light straight up to form a column of light. Counting out loud he walked in the direction the particles were moving until the particles appeared to stop in the beam of light. He said proudly, seven feet per second! The mine ventilation was moving the air at seven feet per second. While I was most impressed with this simple, yet effective measurement method, I was more astounded at the high concentration of fine dust moving through the air and into my lungs. Without the light, it would have been impossible to know how high the dust concentrations were.
After four days of collecting data, we had enough information to determine the air quality in the mining equipment we tested. With this information, the industrial hygienist made specific recommendations to the mine management on engineering controls that would help address the deficiencies in the tested machines. This data was part of the body of knowledge that was used in the development of ISO 23875.
ISO 23875 addresses in a very practical way real-world operational integration issues such as system maintenance, ongoing performance testing, and organizational transparency around these issues. We are indebted to the industrial hygiene community whose heart for people has been poured into the standard to ensure that it works for the operators in their real-world environment.