Tank Venting and Lightning Protection

As leaders and experts in the lightning protection industry, it is our job to identify any problems at your facility and propose the safest solution to protect your assets. In some cases, we even create our own products to accommodate our customers’ needs (read more about the Static Lasso here). It is also our responsibility to shed light on any issues that may have been overlooked in the past. Overhead venting to the atmosphere has been commonplace in the industry for years. However, it presents a bit of a challenge when it comes to protecting tanks against lightning. 

The dangers of venting

Saltwater disposal tanks must be able to breathe to relieve both vacuum and pressure. Vent valves are typically placed on top of tanks to release this pressure. However, venting on top of a tank produces a cloud of flammable gas. Should a direct or nearby lightning strike take place, the flammable gases and vapors around the tank could result in ignition and fire on an unprotected facility. Even if your tanks are outfitted with a lightning protection system, these flammable gases could still pose a threat. 

How can you lower your facilities risk?

There are few options to mitigate your facility’s risk of ignition and fire: 

Both catenary and dissipation lightning protection systems are designed to safely accept a lightning strike and take it to the ground. Because we have seen several issues with the way saltwater disposals and some production facilities are venting flammable gases, certain considerations need to be made when deciding which type of system to install.

• A typical production facility utilizing a vapor recovery system can use either catenary or dissipation as there should be no gases venting during regular operations, and it is safe to collect a strike at both a dissipator and a catenary wire.
• If a production or saltwater disposal facility is venting to the atmosphere above the tank battery and no changes can be made to the venting systems, we recommend installing a catenary system. The increased height of the wire allows us to collect a strike above the vapor space. 
  • Ideally, the safest solution is to divert the flammable gas away from the lightning protection system. All venting should be tied together through a header system and taken outside of the containment a minimum of 50 ft away from the tank battery. This ensures that there is no flammable vapor near the lightning attachment points. Finally, a flame arrestor should be installed at the end of the vent line to ensure fire can not travel back through a vent line to a storage tank.

While proper tank venting is ultimately the responsibility of the facility owner, we can help with the solution to reduce the risk of damage, loss and fires. 

To learn more about tank venting, the risks, and your lightning protection options, contact Michael LeBlanc at mleblanc@petroguardian.com.