NPC-300 brings major changes to Ontario’s environmental noise guidelines
The key conflict which needed harmonization was that the sound level limits in NPC-205/232 for stationary sources (such as industry) were in some cases up to 5 dBA more stringent than those in LU-131. That discrepancy traditionally allowed municipalities to approve a sound sensitive land use, such as a residential development in a location that could force an existing stationary source out of compliance with its Environmental Compliance Approval.
HARMONIZATION TRANSLATES TO RELAXED SOUND LEVEL LIMITS
Evening Limit in Class 1 Areas
In general, NPC-300 has resolved the conflicts in sound level limits among the various superseded guidelines by relaxing the more stringent limit in cases where the previous limits were at odds. One of the most blatant discrepancies was that the exclusion limit during evening hours (19:00 to 23:00) for sound from stationary source in a “Class 1” (Urban) Environment was stipulated as 47 dBA in NPC-205, but 50 dBA in LU-131. NPC-300 has adopted the less stringent limit of 50 dBA for stationary sources in a Class 1 Environment, during evening hours.
Introduction of “Class 4” Areas
Perhaps the most significant change and relaxation of the sound level limits, is the introduction of a new area classification – the “Class 4 area” – with a new, less stringent set of exclusion limits for sound from stationary sources. (The “exclusion limits” represent the applicable sound level limits, except at locations where the characteristic background sound is consistently elevated.) Inherent in the MOE noise guidelines, both old and new, is that the exclusion limits depend on the acoustical character of the area in which the potentially sound-sensitive points of reception reside. Traditionally, there were three classifications in this respect: Class 1, Urban; Class 2, Semi-urban; and Class 3, Rural; with different exclusion limits for each. Perhaps the most significant change and relaxation of the sound level limits, is the introduction of a new area classification – the “Class 4 area” – with a new, less stringent set of exclusion limits for sound from stationary sources.
The concept of the Class 4 area has been introduced to resolve a serious discrepancy that existed between NPC-205 and LU-131, in that LU-131 conferred the “latitude” for the municipal authority to approve a sound-sensitive land use, such as a residential development, in an area where the sound levels of an existing stationary source exceed the MOE sound level limits by up to 5 dBA. If granted, this latitude had the potential to cause the stationary source to contravene its Environmental Compliance Approval, because there was no such “latitude” allowed in NPC-205. NPC-300 has resolved this conflict by eliminating the 5 dBA latitude and instead introducing the definition of the Class 4 area, which has relaxed exclusion limits. Rather than exclusion limits of 50 dBA during the day and evening (07:00 to 23:00) and 45 dBA at night (23:00 to 07:00), which would otherwise apply to a Class 1 area, the exclusion limits for a Class 4 area are 60 dBA during the day and 55 dBA at night, in the plane of a window, and 55 dBA at an outdoor point of reception, such as a residential yard.
Instead of simply extending “latitude” to a developer, as was the case under LU-131, the municipal authority can now designate an area as Class 4, such that the relaxed exclusion limits take effect. In that case, the MOE will consider those relaxed limits to apply to the Environmental Compliance Approval of the stationary source. The important point to note here is that the exclusion limits for the Class 4 area are 10 dBA less stringent than those for a Class 1 area, whereas the “latitude” previously allowed under LU-131 was only 5 dBA. In essence, NPC-300 is 5 dBA less stringent than LU-131 and 10 dBA less stringent that NPC-205, in cases where the background sound is low and the exclusion limits apply.
TWO CHANGES WHICH INCREASE STRINGENCY FOR STATIONARY SOURCES
Although the original motivation for creating NPC-300 was to harmonize the discrepancies among the four superseded guidelines, many other changes and updates have been introduced. As with the revisions described above, most of these miscellaneous changes relax the stringency of the sound level limits or the noise assessment process for certain equipment or situations, but there are two important respects in which NPC-300 increases the stringency for stationary sources.
New Graduated Limits for Impulse Sounds
One such change is the new protocol for assessing impulse sounds. Previously, under the old guidelines, impulse sounds – such as metal on metal impact, firearm discharges or rail coupling sounds – were classified as either frequent or infrequent, and subject to different sound level limits. “Infrequent” was defined as occurring at a rate of less than twenty impulses in any 120 minute period. For infrequent impulses, the sound level limit at a point of reception was 100 dBAI. For frequent impulses, the sound level limit was numerically the same as for non-impulse sounds (e.g., an exclusion limit of 50 dBAI during the day and 45 dBAI at night in a Class 1 environment), except for certain specific industries such as metalworking facilities which had a limit of 50 dBAI regardless of time period. Across the board, this set of exclusion limits is more stringent than the old limits for all scenarios except the case of 9 or more impulses per hour. This increase in stringency has the potential to result in non-compliance with the limits in NPC-300 for facilities that produce impulse sounds and which currently comply with NPC-205/232. There was wide recognition that the dual limit was problematic, because the limit for infrequent impulses was overly lax and the difference in the applicable limit was enormous for impulses occurring nineteen times in 120 minutes versus impulses occurring twenty times in 120 minutes – e.g., 100 dBAI versus 45 dBAI. In NPC-300, there is a new graduated scale of exclusion limits for assessing impulse sounds, depending on whether there are 1, 2, 3, 4, 5 to 6, 7 to 8, or 9 or more impulses occurring per hour. Across the board, this set of exclusion limits is more stringent than the old limits for all scenarios except the case of 9 or more impulses per hour. This increase in stringency has the potential to result in non-compliance with the limits in NPC-300 for facilities that produce impulse sounds and which currently comply with NPC-205/232. As well, the industry-specific impulse sound limits – such as those for metalworking facilities – have been eliminated.
Need to Consider Vacant Lands
Another important change which may make the assessment of stationary sources more stringent is the need to consider hypothetical, potential points of reception on vacant lands that might permit sound-sensitive land uses in future. In past, the MOE had required that Acoustic Assessments consider hypothetical points of reception only on undeveloped residentially zoned lands. More recently, for Approval of renewable energy projects, the MOE had begun requiring Acoustic Assessments to consider potential points of reception on vacant lands with any zoning designation that allows a sound sensitive use. Another important change which may make the assessment of stationary sources more stringent is the need to consider hypothetical, potential points of reception on vacant lands that might permit sound-sensitive land uses in future This could include institutional zones which could conceivably host schools, hospitals or places of worship, agricultural zones which often allow one dwelling per parcel, commercial zones which typically allow daycare facilities, and open space which often allow camping facilities. These changes mean that there are likely to be hypothetical points of reception closer to many stationary sources than the existing bona-fide points of reception which will now need to be considered in future Acoustic Assessments, and may result in non-compliance with NPC-300.
OTHER IMPORTANT CHANGES
Places of Worship
Places of worship located on commercially or industrially zoned lands are no longer considered sound-sensitive points of reception in NPC-300, which represents a relaxation compared to the old guidelines.
Inclusion of Rail Traffic in Determining Background Sound
In certain circumstances, NPC-300 allows sound from rail traffic to be included – in a limited manner – in the quantification of background sound, for the purposes of establishing the applicable sound level limits for stationary sources. This has the potential to relax the limits in some cases, relative to the old guidelines, although there are special conditions restricting the cases in which the rail noise can be included. First is that there must be a minimum of forty trains passing the point of reception in the daytime period from 07:00 to 23:00 and a minimum of twenty trains passing during the night, from 23:00 to 07:00. If this condition is met, then the daytime-average and nighttime-average sound level from the rail activity, less 10 dBA, can be logarithmically added to the limit that otherwise apply.
Periodic Testing of Emergency Equipment
Under NPC-300, periodic testing of emergency equipment – such as a standby generator or firewater pump – is now to be assessed separately from other stationary sources at a given site – not added into a cumulative total. Moreover, the sound level limits for such testing are now specified to be 5 dBA greater (i.e., less stringent) than the limits that would otherwise apply for regular stationary sources. This change represents a fairly substantial relaxation of the limits, for these occasional-use sources.Under NPC-300, periodic testing of emergency equipment – such as a standby generator or firewater pump – is now to be assessed separately from other stationary sources at a given site – not added into a cumulative total.
Exclusion of Infrequent Activities
NPC-300 includes a provision to exclude infrequent activities of a stationary source from the “predictable worst case scenario” considered in an Acoustic Assessment. An activity is defined as frequent and must be included in the predictable worst case scenario if it occurs at least twice per month and emits sound for at least one half hour per occasion. Otherwise, the activity need not be assessed as part of the predictable worst case scenario.
Exclusion of Dwellings within the Property of a Stationary Source
The definition of “noise sensitive land use” in NPC-300 includes the seemingly innocuous provision that a “land use that would normally be considered noise sensitive, such as a dwelling, but is located within the property boundaries of the stationary source is not considered a noise sensitive land use.” This clause was presumably intended simply to address the situation of a home, such as a caretaker’s or employee’s residence, owned by an industry and located on the site of that industry. However, this provision raises some interesting questions, discussed in the following section.
ISSUES AND UNANSWERED QUESTIONS
A number of the changes discussed above raise issues and questions about implementation. The implications of the changes will likely become clear only as the new guideline is applied in practice. Several of these questions are immediately evident, and worth keeping in mind as we move forward.A number of the changes discussed above raise issues and questions about implementation. The implications of the changes will likely become clear only as the new guideline is applied in practice.
Legacy Status of “Replaced” Guidelines Referenced in Existing Documents?
In the release of NPC-300 on the Environmental Registry, the MOE states that NPC-300 shall “replace four existing noise-related guidelines.” It is not entirely clear what “replace” means, with respect to existing Environmental Compliance Approvals that cite NPC-205/232, or with respect to other existing legal documents such as municipal bylaws or Provincial Orders.
Mechanism for Creating Class 4 Areas?
In the final version of NPC-300, the language describing how a Class 4 area comes into existence has been diluted, compared to the first and second draft versions, and leaves the issue ambiguous. Whereas the drafts had stated that a municipal authority would “designate” lands as Class 4, the final version of NCP-300 states that the authority would grant “formal confirmation.” The meaning of “formal confirmation” is not defined and not clear, particularly in terms of how this “confirmation” relates to the provisions of the Planning Act. For instance, could an affected neighbour appeal such a “confirmation” to the Ontario Municipal Board? Will municipalities be comfortable providing such “confirmation” given this lack of clarity?
It is also worth noting that if a municipal authority is not comfortable providing “confirmation” of a Class 4 area, it now has no other latitude or flexibility to allow minor excesses over the sound level limits of NPC-300, even in transitional areas where such an excess may be temporary or of little practical significance.
No More Self-Impact Assessment?
The seemingly innocuous clause that excludes from the definition of a noise sensitive land use dwellings within the property of a stationary source, may have broader ramifications. Specifically, in the case of hospitals, seniors’ residences, and university/college campuses, the MOE has traditionally required that Acoustic Assessments consider “self-impact” of the stationary sources upon the on-site dwelling units, such as patient rooms, or dormitories. It seems that this new clause in NPC-300 does away with the concept of assessing self-impact altogether, because patient rooms and dormitories certainly fall within the definition of “dwelling” in NPC-300, and because “dwellings” within the property of the stationary source are no longer considered to be “noise sensitive.”
Additional Risk for Industry, Developers and Municipalities?
Finally, although many of the relaxations of stringency outlined above will be welcomed by industry and developers alike, we should not overlook the element of additional risk that is being introduced. To the extent that these relaxations result in elevated sound levels impinging upon sound sensitive land uses, there is a risk of a greater number of residents being disturbed by noise, and becoming complainants. To the extent that these relaxations result in elevated sound levels impinging upon sound sensitive land uses, there is a risk of a greater number of residents being disturbed by noise, and becoming complainants. Notwithstanding the numeric sound level limits in NPC-300, Section 14 of the Environmental Protection Act prohibits adverse impact. There have been cases in the past in which the operator of a stationary source has been judged as causing an adverse impact while nevertheless meeting the numerical limits of the NPC guidelines. It is unclear whether this risk has been assessed against the statistical-sociological research available for community response to noise. So, it is also unclear what the community reaction will be to the relaxed sound level limits in NPC-300.
The discussion above does not exhaust the list of changes to the noise assessment process introduced by NPC-300, and surely does not exhaust the issues and questions arising. The MOE has scheduled several information sessions in November 2013 for stakeholders, to discuss the implementation of NPC-300 and answer questions. We can hope that at a minimum, some of the basic questions will be answered about transitioning from the old guidelines to the new. Indeed though, many questions and answers will become clear only as NPC-300 is applied and used across a multitude of projects in future.
HGC Engineering welcomes questions and comments from all affected stakeholders on these changes. We can be reached at firstname.lastname@example.org.