Does nighttime drilling ban apply to PGV?

[pbmaise]

Actually H2S sensors happen to be instruments I used to sell. Two workers in the paper storage warehouse were killed by H2S that made its way up Boise Cascades sewer.

Manufactured by MSA. Mine Safety Appliance.

Despite their expense and a good instrument shop at the mill they had problems too.

One problem is calibration and the cheaper the sensor the more likely they cannot be kept in calibration very long. Winter -35F temps and we suspect the crew were just pretending they did the calibration.

Likely here cheap sensors and not understanding calibration must be often.