Stage II Vapor Recovery Decommissioning in Maryland

A recent shift in the regulatory landscape has been welcomed by owner/operators of fueling stations. After a 2012 EPA ruling stating that Stage II vapor recovery had been made obsolete by onboard refueling vapor recovery (ORVR), many states are allowing gas stations to phase out their old Stage II vapor recovery systems. ORVR is the recovery of fuel vapors in the vehicle itself, while Stage II is the recovery of vapors at the gas station during the fueling process.

As a result, many gas dispensing facilities are moving forward with stage II vapor recovery decommissioning as a cost saving measure. In Maryland, the Department of the Environment is allowing new or modified facilities to be constructed without Stage II systems. Learn more about what this means and how Tanks Direct can help decommission your facility’s old systems, in our blog.

stage-ii-vapor-recovery-decommisioning

Stage II vapor recovery decommissioning can lower operating costs for gas dispensing facilities.

 

Stage II Vapor Recovery Decommissioning

In Maryland

Maryland now allows new or modified gasoline dispensing facilities “to be constructed with appropriate new technologies but without Stage II systems.” According to the MDE, the definition of such a facility is one that on or after March 6, 2014:

  1. begins dispensing fuel for the first time;
  2. excavates below a shear valve or tank pad in order to repair or replace its Stage II system or an underground storage tank;
  3. installs a new dispenser system manufactured without a Stage II system;
  4. undergoes a major system modification consisting of the replacement, repair or upgrade of at least 50% of a facility’s Stage II vapor recovery system.

Owner/operators must notify the MDE of their intentions to act in accordance with MDE policy before performing Stage II vapor recovery recommissioning in order to qualify for enforcement discretion.

Decommissioning and Storage Tanks

Decommissioning Stage II vapor recovery systems has the effect of creating a negative pressure in underground storage tanks, as a result of a system component that is used to maintain an equillibrium or slightly positive pressure in the tank.

Pressure/vacuum vent valves can be used to relieve negative pressure to a degree, but operators should be aware that “This can cause inaccurate UST tank level readings when stations use the stick measurement method.” (PEI Journal) To address this, operators can vent the tank with the vapor hose to release negative pressure prior to taking a stick measurement.

Electronic measurement devices are not affected and will continue to be accurate.

Using Stage II and ORVR Together

Using Stage II and ORVR together can actually cause the release of vapors, which is exactly what both systems are trying to avoid. When the two systems are used in conjunction, air, not vapors, gets pulled back into the tank. Air expands to a greater volume than vapor, which creates a positive pressure in the tank. This can cause the pressure relief valve to open and release vapors.

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This entry was posted on Thursday, August 20th, 2015 at 4:31 pm . You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.