Construction Noise
Construction and development projects are by their nature not quiet. However, with careful planning and operation, it's possible to minimize potential noise disturbances from construction activities. Construction workers, contractors and engineers, should be aware of how activities are regulated under the Montgomery County Noise Control Law (PDF).
If after reading this information you believe a construction site is in violation of the Montgomery County Noise Control Law, file a Two-Party Noise Complaint.
Construction Noise Basics
Virtually all potential noise sources that operate permanently or semi-permanently can be designed or controlled to meet the receiving property line standard. Likewise, potential sources under human control, such as electronically amplified sound, can be designed to meet the law requirements.
Noise from some construction activities, however, is difficult, if not impossible, to control to the receiving property line. This is because the engineering design and technical controls that are effective on stationary sources aren't practical or reasonable for a temporary, often mobile, noise source.
The Noise Control Law, therefore, contains certain standards specific to construction noise. DEP has several tools available to help mitigate and regulate this potential source of disturbance.
Construction Noise Exemptions and Standards
The Montgomery County Noise Control Law defines construction as temporary activities directly associated with site preparation, assembly, erection, repair, alteration, or demolition of structures or roadways. Construction noise levels must be measured on a receiving property, but no closer than 50 feet from the noise source.
Notice to Contractors
From 7 am to 5 pm weekdays, construction noise levels must not exceed:- 75 dBA without a Noise Suppression Plan
- 85 dBA with a Noise Suppression Plan
Download Noise Suppression Plan Guidelines (PDF)
At all times other than 7 am to 5 pm weekdays, the general guidelines in the Noise Control Law must be met. The following table provides a summary of the noise standards for construction activities:
| Time of Day |
Residential
|
Non-residential*
|
|---|---|---|
| Weekday: 7 am to 5 pm (exempted hours) | 75 dBA (85 dBA with a Noise Suppression Plan) | 75 dBA (85 dBA with a Noise Suppression Plan) |
| Weekday: 5 pm to 9 pm (daytime hours) | 65 dBA | 67 dBA |
| Weekday: 9 pm to 7 am | 55 dBA | 62 dBA |
| Weekends and Holidays**: 9 am to 9 pm (daytime hours) | 65 dBA | 67 dBA |
| Weekends and Holidays**: 9 pm to 9 am (nighttime hours) | 55 dBA | 62 dBA |
*In most circumstances in the County, the receiving property will be considered residential.
Be Aware! Construction activities are also subject to the "Noise Disturbance" provisions of the Law. Although a noise disturbance could conceivably occur at any time, it is most likely to happen during nighttime hours. The following are examples of noise disturbances:
- The delivering materials or equipment;
- The Loading or unloading in a residential area; or
- The operating of construction equipment with audible backup warning devices.
The County mails copies of the Law upon request. If you have questions or comments, contact 311 .
Tips for Construction Site Managers
Useful tips learned from previous construction projects include the following:
- Incorporate noise control considerations in all phases of project design and planning.
- Communicate with the surrounding community early and often. Put a human face on the project and the company. Let people know what's happening and, most importantly, when it should be over. People are more tolerant when they know what to expect.
- "Buy quiet----Rent quiet." Select equipment for its low-noise-emission design. When renting, specify the quietest equipment available, using the Noise Control Law requirements as a guide. Low-noise equipment is often of better quality and durability. Most manufacturers can provide noise emission specs.
- Internal combustion equipment should be equipped with proper, well-maintained mufflers. In particular, use "critical" mufflers in noise-sensitive areas. Keep access doors and hatches closed when the units are in operation, and operate all equipment at the minimum level necessary to get the job done. (It saves fuel too!)
- Whenever possible, schedule the more noise-intense activities for less intrusive times, such as mid-morning to mid-afternoon. Use the local power grid to reduce the use of generators and internal combustion powered pumps.
- Construct portable barriers around noisy non-mobile pieces of equipment, using readily available materials.
- Use lawful alternatives to factory-installed backup beepers, such as flagpersons, "Smart Alarms," or video systems. Configure the site to maximize forward movement and minimize backing.
- Prohibit the slamming of tailgates. Advise all delivery and onsite dump truck drivers of noise mitigation procedures prior to work.
- Avoid prolonged idling of equipment. If equipment is not utilized for long periods, operator should shut off equipment to reduce idling noise.
- Purchase a sound level meter for self-monitoring and documentation.
- "Work quiet." Equal to all of the above is the awareness that noise control is an important part of the job. Everyone likes a good neighbor. Managers and supervisors should communicate that noise control is part of the job.
- Noise suppression measures can be fabricated on-site using materials at hand. Also, many equipment manufacturers provide silencing packages, both design and retrofit.
Proactive and reasonable control of construction noise results in more content communities and successful, on-schedule projects with a minimum of hassle due to noise. It also removes the inconvenience of civil penalties, abatement orders, or stop work orders.
Calculating Sound Intensity
Noise emissions from all mechanical equipment must be expressed, in A-weighted decibels (dBA), measured at a stated reference distance. It's your responsibility to calculate the estimated sound intensity (in dBA) to ensure that it complies with the Montgomery County Noise Control Law. The following guidance can help you:
- As a general rule, sound from a stationary source will diminish approximately 6 dBA with each doubling of distance. For example, if the sound intensity is 75 dBA at 25 feet, it will be 69 dBA at 50 feet and 63 dBA at 100 feet.
- Because of the logarithmic nature of the decibel scale, if two sources of equal sound intensity are placed in close proximity to one another, the net increase will be 3 dBA. However, if there is a difference of 10 dBA or more between the two, the lesser source will have no effect on the overall level.
These estimations are especially useful in determining equipment or facility placement (e.g. loading docks), or in the design of engineering controls. All calculations and assumptions should be submitted to the reviewing authority.
Note: Most equipment manufacturers, and especially those who produce or market in Europe or Asia, have detailed noise performance specifications for their products.