Turnaround Season: Getting Your Gas Detection Fleet Ready Before the Shutdown

Fall turnaround season concentrates a year's worth of gas detection demand into a few weeks. Headcount on site multiplies, confined space entries spike, and instruments that spent the last quarter in a cabinet get handed to people who did not calibrate them. Calibration readiness is one of the easier parts of turnaround prep to get right, and one of the more expensive to get wrong.

Count the instruments before you need them

Start with a physical inventory, not a spreadsheet. Confirm how many monitors you actually have, which sensors are installed in each, and which are past their expected sensor life. Electrochemical sensors have a finite service life regardless of use, and a sensor that passes calibration in September may not hold through a six-week outage.

Note which units belong to you and which are coming with contractors. Contractor-owned instruments are the most common gap in turnaround gas detection programs, because nobody has clear ownership of verifying them.

Set the verification standard now, in writing

OSHA's guidance points to ISEA's recommendation that sensor accuracy be verified before each day's use, with full calibration performed on the manufacturer's schedule or after any failed bump test. Typical manufacturer calibration intervals fall between 30 and 180 days.

During a turnaround, decide in advance:

• Who performs the daily bump test, and where the station lives
• Whether contractor instruments must meet your standard or theirs
• What happens to an instrument that fails a bump test at 5 a.m. with a crew waiting
• Where the calibration record is written down, and who reviews it

That last point matters most after the fact. Turnaround records are the ones auditors ask for, because that is when the exposure was highest.

Do not let gas supply be the constraint

Daily bump testing across a larger fleet burns calibration gas far faster than routine operations. Teams that plan cylinder quantities off normal-month consumption run short in week two, and reactive gases like H2S and Cl2 are exactly the ones with the shortest shelf life and the longest reorder pain.

Two things help. First, calculate consumption from turnaround headcount and entry counts, not from last quarter's usage. Second, remove the reorder dependency where you can. On-demand generation produces gas at the point of use, so a bump station does not go down waiting on a freight shipment of cylinders.

Build the buffer in

Assume some sensors will fail during the outage. Have spare sensors, spare instruments, and a defined swap procedure. An instrument out of service for a week during normal operations is an annoyance; during a turnaround it stops an entry.

If you are sizing gas supply for a fall outage now, our calibrators and sources ship same day, so a shortfall in week two does not become a work stoppage. For H2S and chlorine specifically, see the H2S and Cl2 collections.