Gas pipeline compressor building ventilation requires more than just purchasing a couple fans. In our experience, each facility is unique in its own way so there’s not a one-size-fits-all solution for pipeline compressor station ventilation.
Taking into account the following 6 factors will bring you closer to a smart solution for compressor station ventilation.
1. HOW DO I DETERMINE THE CORRECT AIR CHANGE RATE?
Any enclosed compressor building will require a certain number of air changes per hour. At the point where a natural gas pipeline meets a compressor, there can be some leakage into the air. If too much gas builds up in the air, not only can it be hazardous for workers’ health, but a small spark from an electrical component could potentially cause a fire or explosion.
The National Fire Protection Association (NFPA)’s National Electric Code (NEC) sets different hazardous area classification standards for electrical systems. For example, a Class I, Division 1 facility would require explosion-proofing around its equipment. By increasing the air changes in a facility, one might be able to declassify their facility from Division 1 to Division 2, allowing them to avoid some costly explosion-proof equipment.
The standards set by the American Petroleum Institute (API) Recommended Practice 500 indicate the appropriate number of air changes necessary to keep a building within acceptable classifications. In Section 6.3.2.4.2, they advise:
“Enclosed areas (rooms, buildings, or spaces) that are provided at least 0.028 cubic meters (1.0 cubic foot) of air volume flow per minute per square foot of floor area, but at least six (6) air changes per hour, can be considered as adequately ventilated.”
Heat rejection in terms of BTU/hr also needs to be considered. If your equipment is producing a large amount of heat, additional air changes may be required to meet classification requirements. Too much heat in the building can also cause machinery to break down.
And finally, building size will have a large impact on your calculations. Clearly, for a larger building, you’d need more powerful ventilation equipment to achieve your air changes than in a smaller building.
2. IS THERE AN ACOUSTIC REQUIREMENT FOR COMPRESSOR BUILDINGS?
There are no official acoustic regulatory requirements for compressor stations, but acoustic treatments are often necessary for worker comfort and community acceptance.
For stations located in remote areas, the compressors and surrounding equipment may not even be housed within a building. With no one to hear how much noise the equipment is making, there’s no need to silence it!
Quite the opposite is true for compressor stations located in or near residential areas. The compressors are housed within an acoustically treated building. Once the walls are cut to install ventilation equipment, silencers need to be installed to prevent noise from escaping the facility.
3. HOW DOES THE BUILDING SIZE AFFECT THE SYSTEM?
Building size will affect many aspects of the ventilation system. A small compressor building, for example, may only require a small supply fan and a louver. A larger building, however, might require both supply and exhaust fans. The larger the building, the more horsepower required to move the air at an acceptable change rate.
4. HOW DOES THE DRIVE ON THE COMPRESSOR AFFECT THE BUILDING VENTILATION DESIGN?
It doesn’t affect the ventilation system per se, but the type of drive used will determine whether you need a motor cooling system to maintain machinery integrity and prevent hazardous conditions.
A compressor can be powered by a reciprocating engine, gas turbine, or electric motor; each option has its pros and cons. For systems with electric motors, we recommend installing a motor cooling system. This system cools and forces ambient air into the motor to keep the electric wires from overheating.
5. WHICH AGENCIES ARE RESPONSIBLE FOR MONITORING PERFORMANCE?
The NFPA and API provide recommendations and guides for station design, as described above. The Federal Energy Regulatory Commission (FERC) is responsible for regulating the transmission of electricity, natural gas, and oil over state lines.
6. WHAT IF MY COMPRESSOR BUILDING ALREADY HAS A VENTILATION SYSTEM, BUT IT’S NOT PASSING REGULATION INSPECTIONS?
We have retrofit this type of equipment many times and experience tells us that no two systems are exactly alike. Therefore, we recommend you reach out to a trusted ventilation engineering group. At Eldridge, we’ve been working on gas pipeline compressor building ventilation for over 30 years. Contact us today to speak with an engineer about your particular situation.