PIR Noise Management
How PIR handles sound levels:
In a 1989 agreement with North Portland neighborhood groups, Portland City Council recognized the importance of the track as a recreation and tourism site, as well as the negative sound impact on nearby neighborhoods from some events.
At that time:
* council established the current sound limits
* restricted normal track operations to levels consistent with City of Portland Code
* allowed for four “varianced†events that could exceed that basic limit for spectator events.
* set up a neighborhood trust fund for mitigation for those four louder events.
Non-varianced events (the daily operations) follow basic City code, meaning:
* -105 dBA limit measured trackside, which theoretically translates into 65 dB at the property line of the closest residence to the track, across Columbia Boulevard in the Kenton neighborhood.
* -In other words, except for four events, the track operates with the same noise restrictions as any industrial site in the city in relation to residences.
The four varianced events include one event at 110 dB, two at 112 dB and one at 115 dB.
At 115 dB trackside:
* -sound levels at the closest residence to PIR should be 70-75 dB
* -This equals normal traffic noise levels measured for homes along Columbia Boulevard
* -It is 10 dB higher than basic City Code allows for residential or commercial/industrial noise.
For a sense of perspective:
* Normal human conversation ranges between 44 and 65 dBA when people are about 3 to 6 feet apart
* The smallest change in noise level that a human ear can perceive is about 3 dBA
* For most people, a 10 dBA increase in noise levels is judged as a doubling of sound level, while a 10 dBA decrease in noise levels is perceived to be half as loud.
To put PIR sound levels in perspective with measurements in the neighborhood:
Train warning horns at residences along Columbia Blvd. 100 dBA
Truck or motorcycle traffic in street outside residences 90 dBA
Heavy truck traffic noise at residences along Columbia Blvd. 80 dBA
Loudest variance (115dB variance) noise levels at closest residence 75 dBA
Average daytime noise levels residences along Columbia Blvd 70 dBA
Average nighttime noise levels along Columbia Blvd. 60 dBA
Normal PIR operations (105 limit) measured at closest residence 60 dBA
“Loud†days:
* -Four varianced events, including test days, meant fewer than 20 event days during the last season where levels were above 105 dBA
* -More than 620 event days ran at or lower than 105 dBA. (Each particular event on a given day counts as an event day, i.e. a motorcycle track event during the day and a bicycle race at night would mean 2 event days.)
* -A great majority of event days operate at 90 dBA or less, meaning they aren’t audible at any point in the neighborhood, and if measurable would be 50 dBA or less in the neighborhood.
How PIR Monitors Sound Levels:
PIR operates a fixed microphone, 50 feet from the track, just past the “B†bleacher on the front straight. This spot was chosen to best capture highest sound levels from the various kinds of events help at PIR.
The microphone is attached to a digital sound monitor. The data is then captured on a computer. All the noise files are held, and given to the City’s Noise Control Officer on demand.
In addition to the fixed monitor, user groups are required to have a person in charge of each event to monitor sound levels and remove vehicles from the track that exceed the limit (actually they use 103dB, rather than the Code 105 dB). Typically a vehicle that exceeds the limit is black flagged (taken off the track) and given a chance to make modifications or repairs to be below the limit. A second violation will mean a car will be removed from the competition or event for the rest of the day.
Noise complaints:
Should you have an issue with noise levels from the track, please call the track manager at 504.823.5899. You can also register a complaint with the City’s Noise Control Hotline at 503.823.7350.
Noise Variances:
User groups apply for one of the four noise variances through the City’s Noise Officer and the Noise Review Board, a citizen panel. Typically requests are made for one to three-year variances for the events in the winter and spring before the summer racing season. To find out about upcoming meetings call the Noise Control Hotline at 503.823.7350.
Noise Study:
Commissioner Adams asked for a study of both neighborhood opinions and a technical study of noise in North Portland as it relates to all noise generators, including train and truck traffic, airport noise and PIR operations. The technical study is should come to Council in early 2009, and is being managed by the Noise Control Officer.
The attitude study, done in 2006, with two phone surveys of North Portland residences, found:
* -Noise in the neighborhoods is considered a significant issue by about 10 percent of those surveyed who felt it affected them a great deal.
* -The biggest issues for residents were crime, drug abuse and loud music from cars or neighbors.
* -Three quarters of residents say none of the local noise sources tested is a serious concern for them.
* -Large numbers of these North Portland residents indicate that they are unaffected by noise from Portland International Raceway. Nearly two in 10 say that it affects them, and of these, only three percent say that it affects them "a great deal." Nearly half say that it does not affect them at all.
