VT/EVAC Trailer Inspection Checklist
This bi-annual checklist walks through the key safety and functional checks on VT/EVAC vapor trailers from fire extinguishers, bonding cables, gauges, and valves to carbon and liquid media vessels—so issues are caught, documented, and fixed before the unit goes back into service.
Envent Corporation
12/11/2025
VT/EVAC Trailer Inspection Checklist
This procedure outlines the steps for a bi-annual inspection of vapor trailers, focusing on both dry checks and flow-applied checks to ensure all components are functional and safe.
Inspector Information
Vapor Trailer Number
LIC Plate#
Inspector(s)
Supervisor
Date
Dry Checks (No Flow Applied)
Fire Extinguisher
Inspect the fire extinguisher bracket integrity and its functionality, replace if necessary.
Verify that the fire extinguisher on the unit is ready to use, not damaged, the seal is intact, the UL tag in place, and it is up to date on its annual inspection
Bonding cable reels
Check bonding cables for good wire, proper clamps, and connections. Each unit should have at least two bonding spools.
Test continuity from bonding clamp to trailer deck using ohms meter. Ohms reading should be less than 5.
Are Nitrogen Assembly Checks Needed?
if the answer is "oneOf [Yes]"
Inspect nitrogen bottle brackets integrity and function ability, replace if needed.
Inspect nitrogen manifold, re-tighten all fittings if needed or replace them. Test for leaks with soapy water or snoop.
Inspect integrity of hoses and quick connection fittings going to the carbon vessels. Replace if damage.
Flow tube
Remove DS-300 pitot tube/s and blow out with shop air, inspect and reinsert or replace if needed.
Magneheilics
Ensure no liquid is inside and numbers are readable, replace if needed.
Pressure/Temperature Gauges
Check all 0-15 PSIG gauges integrity, numbers are readable. Verify when valve is closed and gauge removed that pressure goes to 0. Replace if bad.
Inspect all temperature gauges integrity and functionality by pulling it out and apply heat/cold, check that the needle moves accordingly. Ensure all vessels have one Temperature gauge and thermowell.
Witch's Hat
Remove and power wash demister pad with degreaser. Inspect integrity.
K.O. Pot
Open KO Pot lid, pull demister pad, and power wash it. Drain any liquid. Ensure drain port is operational. Check gasket integrity and replace it if necessary.
Inspect sight glass, clean it and ensure both valves are open. Replace if needed.
Check valve
Inspect check valve integrity. Replace if needed. Ensure that it is facing the right direction, look for the arrow.
Flame Arrestor
Remove, Inspect, and Clean FA.
PRV & VRV
Ensure PRV & VRV are in a vertical position and had been tested recently, (Ask and Engineer). Replace if needed.
Sample ports
Ensure there is a sample port for inlet, midpoint and outlet of the system.
Ensure sample ports are functional. Replace fitting, valves etc. if needed.
Liquid Media Vessel (Lead Vessel)
Liquid Media Vessel (Lead Vessel) on Trailer?
if the answer is "oneOf [Yes]"
Inspect the inside of the vessel to verify the integrity of the coating and carbon header. Tag vessel out if coating or header are compromised.
Ensure drain port is operational and has a 2" Male camlock at the end.
Inspect gasket and ring clamp. Replace them if needed.
Carbon Vessels
Inspect the inside of each vessel to verify the integrity of the coating and carbon header. Tag out any vessels if coating or header are compromised.
Ensure nitrogen inlet port is operational and ready to use when needed.
Inspect gaskets and ring clamps. Replace them if needed.
Inlet Butterfly Valve
Remove and inspect rubber seal on the inlet valve. Ensure it is operational. Replace if needed.
Camlock Fittings
Inspect all camlocks fittings. Ensure they are operational. Replace if broken or missing ears (Camlocks).
Trailer Aesthetics
Power wash the complete trailer or touch up with paint if vessels do not look presentable. Check decals are readable. Replace if needed.
Flow Applied (500 CFM Blower)
Flow Element (500 CFM Blower)
Ensure magneheilics functionality, needle moves when increasing or decreasing flow.
Record max Flow
Meter name
Unit
Finalization
Comments and Repairs Made
Inspector's Signature
Click here to sign
Supervisor Signature
Click here to sign
Source: Envent Corporation (Community Member)