As industrial areas experience encroachment with residential and commercial areas and regulators look to minimize the potential odour and fugitive emission effects from industry on communities, facilities need to identify effective tools to measure and evaluate the potential for fugitive emissions from their operations. When considering on-property releases, one important item to determine is the potential for fugitive odour and contaminant emissions. Fugitive emissions differ from point source emissions in that point sources have one discernable emission point and can more easily be routed to ventilation and controlled, whereas fugitive emissions can have multiple sources and are difficult to route to ventilation and/or control devices. As such, methods to identify and assess potential fugitive emissions are of vital importance to understanding potential fugitive emissions from a facility.
Tools to Determine Potential Fugitive Emissions
Effective tools to help better understand potential fugitive emissions from industrial facilities include conducting Building Envelope and Negative Pressure Studies. Building Envelope Studies evaluate the outside of the process buildings and determine the likelihood that fugitive emissions could emit from permanent openings in the envelope of the building. Negative Pressure Studies are similar and include internal pressure gradients between rooms within a facility. These studies can assist in determining any leaks in the building that require fixing and gradients between production and other rooms within a facility. In addition, they can aid in understanding how certain operations affect the negative pressure of a building including things such as bay door opening policies, loading/unloading procedures and can be used in preparing standard operating procedures for activities to minimize or eliminate fugitive emissions.
US-EPA Method 204 as a Cost-Effective Solution
Conventional methods of evaluating a building for fugitive emissions can be expensive and/or invasive to operations. When conducting a building envelope or negative pressure study for fugitive contaminant and odour evaluations, Trinity utilizes a less expensive and less invasive method of evaluating the integrity of a building envelope through the application of the procedures in US-EPA Method 204, Criteria for and Verification of a Permanent or Temporary Total Enclosure. Trinity is experienced in preparing a test plan utilizing this method which does not require a facility to shut down or alter operations when the study is conducted. No large fans and only small amounts of tracer smoke is required. No large equipment is required, and it can be carried out by two operators with handheld equipment. Accessibility to rooftops or elevated portions of the facility via lift are sometimes required. This method has been accepted by regulators to test building envelopes for fugitive odour emission concerns in order to demonstrate compliance with permit requirements.
Trinity utilizes a combination of techniques to determine the potential for fugitive odour emissions from a process building, by following the specifications in US-EPA Method 204. By surveying the site and determining if there are any Natural Draft Openings (NDOs), which are any permanent openings in the building excluding doorways or other designed openings, Trinity can determine if the airflow at these openings is inward or outward. Techniques for determining inward or outward airflow include collecting face velocity measurements and differential pressure readings (e.g., change of pressure from outside to inside of buildings). Facial velocities are determined by collecting multiple measurements across the NDO and averaging the readings.
Negative pressure readings are determined by collecting pressure readings across the building envelope (ie. Pressure gradient from outside to inside the building). A facility maintaining negative pressure would experience inward air flow into the building rather than air escaping the building. Smoke tests (via smoke candles, involving small amounts of smoke) can also be conducted as a visual test of airflow direction. Any permanent openings in the building envelope identified through this method which may contribute to fugitive odour emissions can be identified and fixed. Examples of corrective actions could include closing holes in the building façade, sealing gaps in conveyance devices and adjusting fan speeds. A Building Envelope Study, in conjunction with other on-property or off-property contaminants or odour measurement and management tools (e.g., source testing, best management practice plan, neighbourhood monitoring) can assist facility operators in understanding the potential for odour and contaminant emissions and help minimize the potential for neighbourhood impacts and complaints.
Regulatory Requirements
Trinity has seen some examples of regulatory requirements for industrial facilities to confirm their operations are under negative pressure. The Greater Vancouver Regional District (GVRD) has issued air permits which require an initial Building Envelope Study along with regular interval updates to ensure negative pressure is maintained over the life of the permit. In Ontario, the Technical Standard to Manage Air Pollution for Foundries includes a requirement for building pressure studies on buildings. These building pressure studies are included in the larger requirement for reducing fugitive emissions including ventilation studies. When the Ministry of Environment, Conservation and Parks (MECP) conducts inspections of facilities in Ontario, their inspections have sometimes included a review of the requirements in the Technical Standard. Trinity has also seen permit language requiring the use of streamers to confirm inward airflow in process buildings.
Conclusion
In some cases, Building Envelope Studies and/or Negative Pressure Studies are not required by a permit or jurisdiction. However, these studies can be a relatively inexpensive, minimally invasive way to help determine if your facility is under negative pressure. Addressing potential fugitive emissions of contaminants or odours may reduce the potential number of nuisance complaints received from surrounding neighbourhoods.
The key to understanding the potential for fugitive emissions at your facility is to conduct a thorough assessment of your facility. Trinity Consultants can support your facility by outlining an odour assessment plan, implementing the plan, measuring contaminants and odour at your facility, and determining the likelihood for fugitive emissions from your facility. Trinity can help design, implement, and maintain your facility’s Building Envelope and Negative Pressure Study to protect your Facility.
If you have any questions on any of the information discussed in this article or are looking for any fugitive contaminant or odour emissions related support, please contact Steve Babaris from our Trinity Toronto office at 647.501.0358.
