Transmission Operator Eliminates Venting Across Seven Pig Launcher and Receiver Drawdowns Using ZEVAC Mobile Equipment

Gas-Pipeline integrity management depends on pigging, the process of running specialized tools through pressurized pipelines for cleaning, deformation inspection, and in-line inspection (ILI). For gas transmission operators, it's one of the most frequent and operationally critical maintenance activities performed.

The challenge is structural: every standard pigging operation requires venting not once, but twice. To launch a pig, the pipeline must be opened to atmosphere and the launcher barrel depressurized. To receive the pig at the far end, the receiver site must also be fully depressurized before the hatch can be opened. Multiply that across multiple pig runs, cleaning, deformation, and ILI, and the cumulative venting volume becomes significant..

 "These projects were not in high-traffic urban areas but were still close to residential neighborhoods and would have required notifications of the venting/flaring activity  and expected complaints due to the noise it would have caused."

Mandatory Dual-Vent Exposure

Each pig run requires depressurization at both the launcher and receiver - two venting events per run, multiplied across multiple pig types (cleaning, deformation, ILI).

Proximity to Residential Areas

The Fort Lupton site was near residential neighborhoods, making atmospheric venting a public nuisance and notification concern even without a formal urban-area restriction.

High Gas Volume at Stake

Initial drawdown pressures of 600–712 psig across 4 launchers and 3 receivers represented a substantial volume of natural gas that would otherwise be lost to the atmosphere.

Emissions Reduction Commitment

The Transmission Operator's objective was to reduce emissions and prevent purging a large volume of gas, requiring a zero-vent approach across all launcher and receiver operations.

A contracted pipeline crew executed the drawdowns using two ZEVAC Quad units and two rented air compressors, with support from engineering and inspection partners. Instead of venting at the launcher and receiver sites, ZEVAC vacuumed the gas from each barrel and discharged it into an adjacent live section of pipe, eliminating atmospheric release entirely.

Unit placement was confirmed with the operator in advance, prioritizing ease of operation and a clear emergency exit path. After isolating the relevant drawdown and discharge valves, the crew installed valve trees to each valve connection. With compressors warmed up and hoses purged of air, operations proceeded on a tight schedule across three consecutive days plus a follow-up ILI run four days later.

All seven drawdowns were completed without significant delays or incidents. By eliminating venting entirely, the project also avoided the notification obligations, noise complaints, and community friction that traditional venting/flaring would have triggered near residential neighborhoods in Fort Lupton.

All venting and flaring eliminated - zero atmospheric methane release across all 7 drawdowns

No public nuisance complaints or community notifications required

Full depressurization achieved on every launcher and receiver - drawdown to 0–0.3 psig in all cases

Three pig types successfully deployed: cleaning, deformation, and ILI all recovered without issue

Scalable approach - methodology directly applicable to future pigging programs and sensitive-location deployments

The ZEVAC Quad is built for high-volume, time-sensitive gas recovery where multiple compression cylinders are needed to depressurize large-diameter or high-pressure launcher and receiver barrels quickly. Like all ZEVAC equipment, it uses pneumatic positive-displacement cross-compression to transfer gas from an isolated section into a live system with no combustion, no rotating components, and no electronics.