Tank trailer vapor recovery equipment keeps operating personnel on ground
Feb 1, 2005 12:00 PM
RETROFITTING tank trailers to meet new Environmental Protection Agency (EPA) emission standards for loading and unloading certain chemicals also can help keep drivers and/or terminal workers off the top of trailers, which increases safety, said John Freiler of Girard Equipment Inc.
The EPA rule involving the emission standard was published February 3, 2004, in the Federal Register. Freiler made his comments at the National Tank Truck Carriers (NTTC) Cargo Tank maintenance Seminar October 18-20, 2004, in Chicago, Illinois.
Freiler said that a vapor recovery system with a two-inch or three-inch vapor line can be installed that leads from a three-inch opening off the domelid to the bottom of the tank where it can be operated. He warned carriers to be wary after the vent is installed so that the profile does not reach above the silhouette of the overturn rails in order to meet DOT regulations.
It has been pointed out earlier that carriers must work with shippers to get the systems in place within the three-year window of opportunity provided by the EPA rule. The rule requires loading rack facilities to comply with the rule. EPA published the final rule February 3, 2004, in an effort to reduce air pollutants.
The standard applies to transport vehicles (cargo tanks and tank cars) loading at affected transfer racks. Each of these vehicles must have current vapor tightness certification indicating that it has been properly tested for vapor tightness.
If the vehicle is equipped with vapor collection equipment, the vehicle must be tested using EPA Method 27 on an annual basis. For vehicles not so equipped, the Department of Transportation (DOT) leak tightness standards apply, and current certification indicating that these standards have been met must be retained by the owner or operator for each vehicle that loads at affected transfer racks, whether the source owns the vehicle or not, according to the EPA rule.
Some of the equipment installation requires the driver to go on top of the trailer, take the cap out of the cleanout nipple, put in the vapor collection vent, hook the hose on it, and run the hose back to the temporary tank at the loading facility.
Freiler pointed out that with a piped manual vapor control system, top or bottom access is possible. With a hydraulic system, operation is handled from the ground.
He said that if a ball valve and quick coupling or dry disconnect components are chosen, top-of-the-tank handling will be required.
For trailers not equipped with a hydraulic pump, air-operated systems can be used.
A good vapor breaker also is required to insure that the tank does not implode, and there should be a pressure gauge at every ball valve. He also noted that any piping beyond crash protection equipment must have a shear.
In addition to safety and meeting the EPA regulation, Freiler pointed out that the equipment controls odors, which helps eliminate nuisance complaints.
Vapor recovery systems used for collecting displaced vapors during product transfer have long been used in gasoline service.
Carriers should look at several considerations when making a system decision:
A tank with a vapor recovery system must include a good vacuum breaker.
The system and piping must be cleanable and capable of being disassembled.
The system must include pressure gauges so personnel don't open pressurized lines.
Piping that extends beyond crash protection must have a sheer section.
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