Frequently Asked Questions
In order to make some technical topics much easier to understand, we have assembled some of our most frequently asked questions related to ET’s market specialties. Below you will find information on the following topics:
- Compressed Natural Gas Acronyms
- Natural Gas Virtual Pipeline
- Natural Gas Vehicle (NGV) Maintenance Garage Code Compliance
- Leachate Treatment
- Single Stream Recycling
- Landfill Gas Refining
- Portable CNG Fueling
To submit a question, please email firstname.lastname@example.org.
Compressed Natural Gas Acronyms
When reading about alternative and renewable fuels, you may come across numerous industry acronyms and not know exactly what they all mean. While composing a report for the Wisconsin State Energy Office, ET Environmental defined several terms that are most frequently used for natural gas vehicle maintenance garages. For a complete copy of the report click here.
Major Repair Garage – Defined in NFPA 30A as “A building or portions of a building used for lubrication, inspection, and minor automotive maintenance work, such as engine tune-ups, replacement of parts, fluid changes (e.g., oil, antifreeze, transmission fluid, brake fluid, air conditioning refrigerants, etc.), brake system repairs, tire rotation, and similar routine maintenance work, including associated floor space used for offices, parking or showrooms.”
Minor Repair Garage – Defined in NFPA 30A as “A building or portions of a building where major repairs, such as engine overhauls, painting, body and fender work, and repairs that require draining of the motor vehicle fuel tank are performed on motor vehicles, including associated floor space used for offices, parking, or showrooms.”
ACH – Air Changes per Hour
AHJ – Authority Having Jurisdiction
ATS – Automatic Transfer Switch
CFM – Cubic Feet per Minute
CFM/FT2 – Cubic Feet per Minute per Square Foot of Floor Area
CFM/FT3 – Cubic Feet per Minute per Cubic Foot of Room Volume
CNG – Compressed Natural Gas
DSPS – Wisconsin Department of Safety and Professional Services
ESD – Emergency Shut Down
FAT – Factory Acceptance Testing
IBC – 2009 International Building Code
IEBC –2009 International Existing Buildings Code
IECC – 2009 International Energy Conservation Code
IFC – 2009 International Fire Code
IMC – 2009 International Mechanical Code
IRH – Infrared Heating
LEL – Lower Explosive Limit
LNG – Liquefied Natural Gas
MAU – Makeup Air Unit
NEC – National Electric Code 2008 (NFPA 70)
NFPA – National Fire Protection Association
NFPA 30A – National Fire Protection Association: Code for Motor Fuel Dispensing Facilities and Repair Garages, 2008
NFPA 52 – National Fire Protection Association: Vehicular Gaseous Fuel Systems Code, 2010
NGV – Natural Gas Vehicle
O&M – Operations and Maintenance
OWS – Oil-Water Separator
PSI – Pounds per Square Inch
Natural Gas Virtual Pipeline
From the perspective of the end user, a virtual pipeline emulates an actual connection to a natural gas pipeline. Natural gas is available whenever needed. The actual logistics involve loading a natural gas tanker at one location, transporting it, and connecting it at the end user’s location. As the gas is depleted, a new tanker is brought in and the depleted tank refilled.
A broad spectrum of facilities use a virtual pipeline. A virtual pipeline might supply an industrial facility for their boilers or other processes, it may supply an LNG liquefaction plant, or a CNG compression/fueling station.
Natural gas supplies in the United States have increased with the fracking boom. Such supplies have resulted in gas costs dramatically lower than diesel or propane fuel. Where pipeline gas may not be readily available, a virtual pipeline allows users to reap the benefit of this lower cost, clean fuel.
There will be an additional cost for transportation to the user’s facility, but the total cost will still generally be less than traditional fuels in most cases. Inclement weather in certain parts of the country may hinder delivery to the owner, but this can be mitigated with additional buffer storage.
Natural Gas Vehicle (NGV) Maintenance Garage Code
The code requirements are in several different documents which is partially why the topic of garage retrofit is confusing. The actual code adoptions vary by jurisdiction but the majority of the code provisions are in NFPA 30A, NFPA 70, International Fire Code, International Mechanical Code, and the International Building Code.
The industry standard for the definitions are in NFPA 30A however, the International Fire Code does provide exemptions based on its description of “Minor” repair activities. The NFPA 30A definition of a Major Repair Garage is as follows:
“A building or portions of a building where major repairs, such as engine overhauls, painting, body and fender work, and repairs that require draining of the motor vehicle fuel tank are performed on motor vehicles…”
The codes are written such that the garage gets the classification of Major or Minor and not the maintenance on any particular vehicle. This is generally the enforced interpretation as well.
The four areas that typically require retrofit in an existing garage are Heating, Ventilation, Gas Detection, and Electrical systems. More information can be found in in the guidelines document written by ET Environmental for the Wisconsin State Energy office.
This may be difficult in most geographical locations because there have been so few upgrades done to date. ET Environmental provides design and construction services for repair garages and NGV fueling infrastructure throughout the nation.
Costs vary significantly and most projects are $15,000 to $70,000 per truck maintenance position depending on the scope of work and existing conditions.
One of the most common ways to reduce costs is to limit the area that is retrofitted for NGVs. In addition, use experienced designers and contractors to avoid costly misinterpretations of the confusing and sometimes conflicting requirements.
Leachate is water that has come into contact with waste in a landfill or composting facility. This can be through precipitation, in the waste itself, from cover material, or formed in reaction as the waste decomposes.
In the case of landfills, every effort is made to prevent pollution. Modern landfills are built with liners and collection systems for the leachate. Leachate is extracted from the landfill to protect nearby groundwater from contamination.
Depending on the waste in the landfill, leachate may contain high levels of organic and inorganic pollutants such as pathogenic micro-organisms, ammonia, benzene, heavy metals or other toxic substances. High temperatures and corrosion have also caused an increased need for leachate treatment.
With stricter environmental permits, many municipal waste water treatment plants (WWTP) are having difficulties meeting the contaminant levels of the new requirements without expensive upgrades or limiting the liquids they accept. Because of this, landfills are being forced to pre-treat their leachate before it can enter the sewer system. Another reason for leachate pre-treatment is that many WWTPs are upgrading to ultra-violet (UV) disinfection. The UV requires a certain transmittance of the liquid to work effectively, and leachate rarely meets that without pre-treatment.
Treating of landfill leachate can include evaporation ponds, constructed wetlands, or removal from site for treatment either via hauling or sewer system. In recent years, many landfills have started to build on-site leachate treatment plants. Leachate treatment plants may include aeration, pH adjustment, aerobic and/or anaerobic digestion, filtration, sludge dewatering, and temperature change.
Leachate can be recycled back through the landfill to help with the decomposition reactions. Depending on the composition of the leachate, it may also be used for irrigation of non-edible crops.
Single Stream Recycling
Various recycling materials are often considered to be collected and recycled in “streams” of similar materials. For example, glass, plastic, and paper are three common streams of recycling material. Single stream recycling means all of these recyclable materials are collected together curbside rather than sorted by type of material prior to collection. Single-stream is also referred to as “comingled” or “single-sort.”
Rather than having to separate recycling material prior to collection, single stream recycling allows all material to be collected curbside in a single receptacle. Single stream has been shown to increase participation in recycling programs, reduce collection costs, and increase the rate at which solid waste is diverted away from a landfill.
-Single stream recycling makes recycling as easy collecting garbage-all materials are just tossed together in one bin. Making the collection of recycling easier encourages more recycling, which means less waste being deposited into landfills. Single steam recycling is said to increase recycling rates by approximately 30%.
-Collection costs for users are typically reduced with single-stream recycling, as collection is more efficient. With no curbside sorting required, collection vehicles can be automated, making collection quicker, safer, and more cost effective.
-Changing to single stream recycling typically enables communities to accept more types of material. Cardboard and fiber recycling can be expanded to incorporate phone books, junk mail and mixed residential paper.
Single-stream recyclable materials collected from residential areas are typically combined with other business and industrial recyclables and transported to a nearby Material Recovery Facility or MRF pronounced “murf.” A MRF is a specialized facility that receives, sorts, and prepares the recyclable material to be marketed and sold to manufacturers, for re-use.
There are two types of MRFs, clean and dirty. A clean MRF only accepts recyclable material that has already been separated from non-recyclable materials (solid waste). A dirty MRF collects recyclables from a waste stream that includes solid waste. Recovery rates (the amount of recyclable material pulled from the solid waste stream) in a dirty MRF typically exceed the recovery rates of a clean MRF, but require more manpower and are more expense to operate.
These MRFs use a variety of sorting techniques to separate materials into sellable commodities, including metal, aluminum, various grades of plastics, glass, mixed paper and cardboard. A MRF can employ large systems of conveyors, magnets, screens and mechanical devices to sort through the material and separate the single stream material back into separate streams of commodity material for resale. Once separated, the materials are often baled, crushed, compacted or shredded to meet re-sale specifications.
Landfill Gas Refining
Roughly speaking – and there is significant variability – landfill gas contains 45-55% methane, 40-50% CO2 and traces of nitrogen, oxygen and sulfur compounds. Through the refining process, CO2 and other constituents are removed, leaving primarily methane (otherwise known as natural gas). The product is the same gas used in your home or compressed into CNG.
Landfill gas can be used with minimal processing in electrical generators (known as landfill gas to energy, LFGTE) or directly fired in boilers or furnaces for heat or manufacturing.
Generally, if not used for other purposes, landfill gas is burned in a flare. While a flare minimizes greenhouse gas emissions and potential odors, the energy is wasted.
The RFS is an EPA mandate that transportation fuel contains a minimum volume of renewable fuel – refined landfill gas qualifies as a renewable fuel.
Landfill gas is refined to meet pipeline quality specifications and can be used anywhere pipeline natural gas is used. But, when used specifically as a transportation fuel, it carries added value as a renewable fuel, generating Renewable Identification Numbers (RIN’s). RIN’s are tradable, marketed generally to petroleum fuel blenders to demonstrate compliance with the Renewable Fuel Standard (RFS).
Portable CNG Fueling
Equipment selection is unique for each CNG fueling project. Project specific needs and budgets will drive the selection process. ET has worked with all of the major CNG equipment suppliers and can help select a package that is right for your project. We are not affiliated with any particular equipment vendor and can therefore provide unbiased recommendations and guide the owner to a solution that best fits their needs.
This questions can only be answered after considering the specific needs of the station. Will the CNG fueling be used for time-fill, fast-fill, or both? For time-fill systems, several important factors that will need to be investigated include the fleet size, expansion potential, and fueling window. For fast-fill and retail fueling, the customer experience, time required to fill a particular vehicle, or number of vehicles being consecutively fueled may control the station design. Storage capacity and type (3 bank cascade storage or buffer storage) will affect the fuel delivery rate as well.
The fueling rate is only one of many factors that will need to be considered. Redundancy, functionality, expandability, gas quality, and maintenance support are just a few of the considerations. Do you have multiple dispensers that will need a First In – First Out fueling sequence? Will the system be designed for future expansion or increased loads? Do you need the capability to de-fuel vehicles? What do you know about the gas quality and moisture content in your area? It may be appropriate to consider dryers that are larger, have multiple towers, or automatic regen capabilities. ET can help you make all of these decisions and only a detailed conversation about your project in your location will help to develop the best solution to fit your needs.
There are several main types of redundancy that should be considered depending on your needs. First, it’s important to understand the consequence of a fuel system that is not working. Some clients choose to have mechanical redundancy provided by redundant pieces of equipment that can fuel at a reduced rate for short periods of time. Others need full flow redundancy that provide a specified flow rate even when a piece of equipment is down. In some cases, redundancy can be provided by having a nearby backup fueling location. Power outages may be overcome with a temporary or permanent generator setup.