COMMONWEALTH OF MASSACHUSETTS

SECTION 721.560

CONSTRUCTION NOISE CONTROL

Section 1: Description

Section 2: Materials

Section 3: Construction Methods

Section 4: Compensation

Tables and Figures

DESCRIPTION

1.01 GENERAL

A. The intent of this Section is to minimize construction noise within construction areas, lay-down areas, and communities adjacent to the construction site. To this end, the Contractor and all subcontractors, suppliers, and vendors, are required to comply with all applicable noise regulations, specification requirements, and the noise level limits specified herein. This Section supplements the requirements of Division I, Subsection 7.01E. Refer also to Division I, Subsection 8.06, Limitation of Operations, Subsection 7.27, Safety, and Exhibit I-J, Mitigation Requirements

B. This Section specifies requirements for Noise Control Plans, a Noise Monitoring Plan, noise monitoring prior to and during construction, response to community complaints, and equipment certification. All requirements of this Section shall be overseen by an approved Acoustical Engineer employed by the Contractor.

C. The Contractor shall use equipment with efficient noise-suppression devices and employ other noise abatement measures such as enclosures and barriers necessary for the protection of the public. In addition, the Contractor shall schedule and conduct operations in a manner that will minimize, to the greatest extent feasible, the disturbance to the public in areas adjacent to the Work and to occupants of buildings in the vicinity of the Work.

D. In no case shall the restrictions identified in this Section limit the Contractor's responsibility for compliance with all Federal, state, and local safety ordinances and regulations.

E. Related Work specified elsewhere:

Section 850.001 Traffic Control for Construction and Maintenance Operations.

1.02 TERMS USED

A. Noise is any audible sound which has the potential to annoy or disturb humans, or to cause an adverse psychological or physiological effect on humans.

B. Daytime refers to the period from 7 AM to 6 PM local time daily, except Sundays and Federal holidays.

C. Evening refers to the period from 6 PM to 10 PM local time daily, except Sundays and Federal holidays.

D. Nighttime refers to the period from 10 PM to 7 AM local time daily, as well as all day Sunday and Federal holidays.

E. Noise-Sensitive Locations shall mean locations where particular sensitivities to noise exist, such as residential areas, institutions, hospitals, and parks.

F. Nuisance Noise refers to sound levels that annoy or disturb a reasonable person of normal sensitivities, but do not exceed the noise limits specified herein.

G. Lot-line refers to the line separating a parcel of land from another parcel or from the street.

H. Background Noise shall be defined as the measured ambient noise level associated with all existing environmental, transportation, and community noise sources in the absence of any audible construction activity.

I. dBA shall be defined as the sound level (in decibels referenced to 20 micro-pascals) as measured using the A-weighting network on a sound level meter, in accordance with ANSI S1.4 Standards.

J. Lmax shall be defined as the maximum measured sound level at any instant in time.

K. Leq shall be defined as the equivalent sound level, or the continuous sound level that represents the same sound energy as the varying sound levels, over a specified monitoring period.

L. L10 shall be defined as the sound level exceeded 10 percent of the time for a specified monitoring period.

M. Slow specifies a time constant or 1 second for the root-mean-square (RMS) detector used by a sound level meter, in accordance with ANSI S1.4 Standards.

N. Impact noise is noise produced from impact or devices with discernible separation in sound pressure maxima. Examples for impact equipment include, but are not limited to; blasting, clam shovel or chisel drops, pavement breakers, jackhammers, hoe rams, mounted impact hammers, and impact pile drivers ( but not vibratory pile drivers). Table 2 specifies types of equipment which are considered to emit impact or continuous noise.

1.03 SUBMITTALS

A. Submit the name, address, and qualifications of the Acoustical Engineer, as specified in Article 1.05 of this Section, for review and acceptance as required by Division I, Subsection 5.02. This submittal is required prior to preparing the Noise Monitoring and Noise Control Plans, performing any noise monitoring, or initiating any construction activity.

B. Submit the Noise Monitoring Plan prior to construction, as specified in Article 1.06 of this Section, for review and acceptance as required by Division I, Subsection 5.02. The Noise Monitoring Plan shall also contain background noise readings at all the receptor locations identified in Table 3 and Figure 1 of this Section, as described in Article 3.01.B of this Section.

C. Submit a current laboratory calibration conformance certificate for the noise monitoring equipment, as specified in Article 2.02 of this Section, prior to performing any noise level monitoring. Submit updated certificates following subsequent yearly calibrations, or upon completion of repairs to the instrument, for the duration of this Contract.

D. Submit a Noise Control Plan every 6 months as specified in Article 1.07 of this Section, for review and acceptance as required by Division I, Subsection 5.02. The first of these submittals is required prior to construction and no later than 60 Days after Notice -to-Proceed. An updated Noise Control Plan submittal is required every 6 months after the date that the initial Noise Control Plan was due, or more frequently as Work conditions or Work hours change substantively from the conditions described in a previously approved Noise Control Plan.

E. Submit Noise Measurement Reports on a weekly basis during construction as specified in Article 3.01 and 3.02 of this Section. The weekly reports shall include all noise level measurements taken during the previous week, including construction compliance monitoring and any required complaint response investigations.

F. Submit all applicable Equipment Noise Compliance Certification measurements for review and acceptance in accordance with Article 3.05 and Figure 5 of this Section. Once accepted by the Engineer, Equipment Noise Certificates will remain valid for not more than 6 month, or less if subsequent field inspection noise compliance measurements indicate that a given piece of equipment no longer meets it respective 50 ft emission limit as provided in Table 2 of this Section.

G. Submit shop and working drawings, computations, material data, and other descriptions for abatement measures identified in the Noise Control Plan or used as Temporary Noise Barriers, Acoustical Barrier Enclosures, or Noise Control Curtains as specified in Articles 2.04, 2.05, 2.06 of this Section. Drawings and computations shall be stamped by a Registered Professional Engineer of the Commonwealth of Massachusetts as required by Division I, Subsection 5.02.

1.04 CONSTRUCTION LIMITATIONS

A. Noise Levels

1. Daytime, evening, and nighttime construction noise levels at noise-sensitive locations and other noise monitoring locations, as specified in paragraph 1.06.B.1, shall not exceed the lot-line noise limits specified in Table 1. The lot-line criteria shall apply to all points on a given lot-line of an affected receptor.

2. Equipment and associated equipment operating under full load that meets the requirements as specified in Article 1.08 of this Section shall not exceed the Lmax noise limits specified in Table 2. The 50-foot noise emission limits specified in Table 2 shall apply to the entire operation in which the equipment is engaged. Table 2 also provides distinction as to which equipment is considered to emit impact or continuous noise.

3. Work shall be performed in a manner to prevent nuisance conditions such as noise which exhibits a specific audible frequency or tone (e.g., backup alarms, unmaintained equipment, brake squeal) or impact noise (e.g., jackhammers, hoe rams). The Engineer will make any final interpretation concerning whether or not nuisance noise conditions exist. The Engineer has the authority to stop the Work until nuisance noise conditions are resolved, without additional time or compensation for the Contractor.

4. Work performed by the Contractor in the absence of an approved Noise Monitoring Plan, Noise Control Plan, and Equipment Noise Certificates shall be done solely at the discretion of the Engineer. Any Work stoppages ordered by the Engineer as a result of unacceptable noise conditions shall not be grounds for any compensation nor claims from the Contractor.

B. Equipment Operations

1. The use of impact pile-drivers shall be prohibited during evening and nighttime hours (i.e. 6 PM to 7 AM as defined in Article 1.02).

2. Vibratory sheet pile driving shall be prohibited during the nighttime period (i.e. 10 PM to 7 AM as defined in Article 1.02).

3. All jackhammers, chainsaws, and pavement breakers used on the construction site shall be enclosed with shields, acoustical barrier enclosures, or noise barriers as described in an Exhibit at the end of Division II Special Provisions.

4. Use of all impact devices, including hoe rams, jackhammers, chiseling devices, and pavement breakers, shall be prohibited during the nighttime hours (i.e. 10 PM to 7 AM). Any necessary use of impact devices between 10 PM and 7 AM shall be reviewed by the Engineer in advance and allowed as an exception only upon sufficient justification.

5. Contractors shall use approved CA/T haul routes to minimize noise at residential and other sensitive noise receptor sites.

6. All equipment with backup alarms operated by the Contractor, vendors, suppliers, and subcontractors on the construction site shall be equipped with either audible self-adjusting ambient-sensitive backup alarms or manually-adjustable alarms. The ambient-sensitive alarms shall automatically adjust to a maximum of 5 dBA over the surrounding background noise levels. The manually-adjustable alarms shall be set at the lowest setting required to be audible above the surrounding noise. Installation and use of the alarms shall be consistent with the performance requirements of the current revisions of Society of Automotive Engineering (SAE) J994, J1446, and OSHA regulations, and as described in an Exhibit at the end of Division II Special Provisions.

7. Per Massachusetts State regulations, engine idling for trucks is limited to 5 minutes maximum.

1.05 ACOUSTICAL ENGINEER

A. The Acoustical Engineer identified in this Article shall oversee all requirements of this Section. These include the preparation and implementation of the Noise Monitoring Plan and Noise Control Plans, the Equipment Noise Certifications, and the construction and complaint response noise monitoring.

B. The Acoustical Engineer shall have the following minimal qualifications:

1. Bachelor of Science or higher degree from a qualified program in engineering, physics, or architecture offered by an accredited university or college, and five years experience in noise control engineering and construction noise analysis; or current enrollment as a full Member or Board-certified Member in the Institute of Noise Control Engineering (INCE).

2. Demonstrated substantial and responsible experience in preparing and implementing construction noise controls and monitoring plans on construction projects conducted in an urban setting, calculating construction noise levels, and designing and overseeing the implementation of construction noise abatement measures.

C. If at any point, in the judgement of the Engineer, the quality of the Acoustical Engineer’s submittals proves to be repeatedly unacceptable, then the Engineer can require the submittal and selection of an alternative Acoustical Engineer meeting the requirements in this Article.

1.06 NOISE MONITORING PLAN

A. The Noise Monitoring Plan describes the noise monitoring and reporting procedure to be used during construction. The Plan shall be prepared by and bear the signature of the Acoustical Engineer and shall be submitted to the Engineer as specified in paragraph 1.03.B. Noise generating equipment shall not be operated prior to acceptance of the Noise Monitoring Plan.

B. The Noise Monitoring Plan shall identify and describe the following in detail:

1. The receptor locations where noise monitoring will be performed. Include locations identified in Table 3 and shown in Figure 1 and others as appropriate to effectively monitor noise conditions during construction. Include sketches of all locations.

2. The type of noise level measurement device that will be used, as specified in Article 2.02 of this Section.

3. The noise monitoring methods and procedures that will be used, as specified in Article 3.01 of this Section.

4. The data reporting method that will be used, as specified in Article 3.02 of this Section.

5. The response procedure and actions to be taken for any lot-line or equipment noise level that exceeds the noise limits specified in Article 1.04 of this Section. The response procedure may include, but not be limited to, use of noise reduction materials and equipment listed in Article 2.03 and methods listed in Article 3.03.

6. The complaint response and resolution procedures, as specified in Article 3.06 of this Section.

7. Documentation from noise monitor manufacturer warranting that the specific equipment is "Y2K Compliant".

C. The Noise Monitoring Plan shall also contain the Contractor’s submittal of background noise measurements performed in accordance with Article 3.01.B of this Section (provided by the Engineer in Table 5) along with the corresponding lot-line noise criteria limits computed in accordance with Table 1 of this Section for all the noise receptor locations identified in Table 3 and Figure 1 of this Section.

1.07 NOISE CONTROL PLAN

A. The Noise Control Plan describes the procedure for predicting construction noise levels prior to performing construction activities and describes the noise reduction measures required to meet the noise level limitations and minimize nuisance noise conditions. The Plan shall be prepared by and bear the signature of the Acoustical Engineer and shall be submitted to the Engineer as specified in paragraph 1.03.D. Noise generating equipment shall not be operated prior to acceptance of the applicable Noise Control Plan. The initial Noise Control Plan is required no later than 60 Days after Notice-to-Proceed. Updated Noise Control Plans shall be resubmitted every six months thereafter, or whenever the Construction activities or the construction Work hours have changed, as specified in paragraph 1.03.D.

B. The Plan shall include:

1. Contract-specific noise control commitments made previously by the Project as referenced in this Section.
2. A description of the anticipated construction activities.
3. An inventory of construction equipment and associated noise levels using Part A of the Noise Control Plan Form in Figure 2. The following information is required:

   a. Column (a): Code to identify equipment for sketches and equipment certification procedures.

   b. Column (b): Appropriate equipment category from Table 2.

   c. Column (c): Equipment manufacturer and model.

   d. Column (d): Unique identifier (ID), such as registration number.

   e. Column (e): Horsepower rating of the equipment.

   f. Column (f): Equipment noise emission limit from Table 2.

   g. Column (g): Estimated noise level at 50 feet. If greater than the limit specified in Table 2, noise reduction measures will need to be included.

   h. Column (h): Estimated date of first use on site.

   i. Column (i): Estimated date of last use on site.

   j. Column (j): Expected use; circle D for daytime, E for evening, N for nighttime use.

4. Noise Level Calculations

Perform calculations to predict lot-line construction noise during applicable daytime, evening, and nighttime periods. The calculations shall be made for noise monitoring locations as specified in paragraph 1.06.B.1 where noise emitted by all applicable equipment will cause the greatest noise level for each type of land use for a given time period. The Contractor shall provide the results on Part B of the Noise Control Plan Form in Figure 3 with calculations included below the results, and with the locations for the calculations indicated on the site sketch. The noise level calculation procedure shall be as follows:

a. Calculate Lmax:

1. Calculate the maximum equipment noise level at the closest point on the lot-line for each item of equipment using the following equation:

Lmax(equipment) = E.L. - 20 log (D/50)

where:

E.L. is the estimated equipment noise emission level at 50 feet (Figure 2, column g or from Table 2 of this Section) in dBA.

D is the distance from the equipment to the closest point on the lot-line in feet, but shall not be less than 50 feet.

2. Whereas the maximum noise level produced by each piece of equipment may not occur simultaneously, obtain the overall maximum construction noise level at the lot-line from the loudest single piece of equipment as follows:

Lmax(overall) = MAX [Lmax(equipment)]

b. Calculate Leq:

1. Calculate Leq at the closest point on the lot-line for each item of equipment using the following equation:

Leq(equipment)= E.L. - 20 log (D/50) + 10 log (U.F.%/100)

where:

E.L. and D are as defined above in Article 1.07.B.4.a.1.

U.F. is the "usage factor", and is used to time-average the noise levels associated with an operating piece of equipment. The U.F. is expressed as the percentage of time that the equipment is operated at full power while on site. This factor shall be estimated by the Contractor or the Acoustical Engineer. Guidelines for the selection of usage factors are provided by the U.S. Environmental Protection Agency ("Noise From Construction Equipment and Operations, Building Equipment, and Home Appliances", U.S. Environmental Protection Agency Report NTID 300.1, December 31, 1971), or are also provided for use in Table 2 of this Section.

2. Combine the individual contributions of each piece of equipment to obtain the overall construction Leq at the lot-line as follows:

Leq(overall) = 10 log S 10 ^{[Leq(equipment)/10]}

c. Calculate L10:

Finally, as supported by previous construction noise studies, calculate the estimated overall L10 by simply adding 3 dBA to the overall Leq as follows:

L10(overall) = Leq(overall) + 3 dBA

5. Noise Level Limit Calculations

Perform calculations to determine L10 lot-line noise level limits during applicable daytime, evening, and nighttime periods based on the background noise level data as specified in Table 1 and Article 3.01 of this Section. The calculations shall be made for noise monitoring locations listed in Table 3 of this Section. Background noise levels and corresponding lot-line noise criteria limits for this contract have already been established by the Engineer and can be seen in Table 5 of this Section.

a. Determine the L10 noise level limits for daytime, evening, and nighttime time periods from Table 1 based on the background L10 noise levels established in accordance with Article 3.01.B of this Section for each time period (furnished by the Engineer in Table 5).
b. The Lmax noise level limits are absolute limits from Table 1 and do not rely on background conditions.

6. A sketch of the construction site indicating the following:

a. Contract name and number, Contractor's name, date, scale, legend of symbols, and direction of North.
b. Construction equipment locations, designated by codes used in Column (a) in Figure 2.

c. All noise receptor locations near the construction site, as specified in paragraph 1.06.B.1.

d. Locations and types of noise reduction measures that may be required to demonstrate compliance with noise limits as specified in Article 1.04 of this Section.

7. A summary table listing the anticipated unmitigated and, if warranted, mitigated construction noise levels shall be provided for all the noise receptor locations (per Article 1.06.B.1.). Each receptor’s appropriate lot-line criteria limits (from Table 1) shall also be referenced in the table.

8. A description of noise reduction measures, if necessary, to meet the lot-line and equipment noise level limitations as specified in Tables 1 and 2. The noise reduction measures may include, but not be limited to, the noise reduction materials and equipment listed in Article 2.03 and noise reduction methods listed in Article 3.03 of this Section. If noise reduction measures are required, re-calculate the noise levels at the lot-line of the noise monitoring location using the anticipated noise reduction measures and submit the results in Figure 3.

9. Where excessive noise levels are anticipated, noise mitigation measures must be proposed. The beneficial noise reducing effects of the mitigation measures must be quantitatively predicted, and compliance with the specified noise limits in Table 1 must be demonstrated in the resulting predicted mitigated noise levels.

10. Calculations for noise barrier performance design predictions shall use the "path-length-difference" method involving fresnel numbers.

11. Any drawings, sketches and suitable calculations which demonstrate anticipated noise reduction benefits. Submit shop and working drawings, computations, materials data, and other descriptions as specified in paragraph 1.03.G.

1.08 EQUIPMENT NOISE CERTIFICATION

A. The construction equipment to be certified includes any equipment of the types listed in Table 2 brought on-site. Noise emission limits in Table 2 shall apply to Contractor and subcontractor equipment.

B. All construction equipment shall be tested using the procedures specified in Article 3.05 of this Section to ensure compliance with equipment Lmax noise limits in Table 2. The equipment noise certification shall be overseen by the Acoustical Engineer and certificates shall be submitted to the Engineer as specified in paragraph 1.03.F.

C. Equipment shall be tested every 6 months while in use and shall also be subject to periodic compliance testing whenever evidence of non-compliance is apparent. Testing shall be performed as described in Article 3.05 of this Section.

D. Equipment without a currently valid noise certification on file with the Engineer, or equipment that fails its random noise compliance test (i.e. exceeds the 50 ft emission limits in Table 2) shall be required to cease operation until adequate mitigation measures can be implemented.

MATERIALS

2.01 GENERAL

A. All equipment and materials specified in this part will remain the property of the Contractor or Contractor's subcontractors, vendors, and suppliers, as applicable.

2.02 NOISE MONITORING EQUIPMENT

A. All noise measurements shall be performed with an instrument that is in compliance with the criteria for a Type 1 (Precision) or Type 2 (General Purpose) Sound Level Meter as defined in the current revision of ANSI Standard S1.4.

B. The sound level meter shall be capable of measuring dBA noise levels and operating on the "slow" response setting.

C. Sound level meters shall be capable of measuring and displaying Lmax and L10 over 20 minute intervals in the field without the need for post-processing of data.

D. All sound level meters, microphones, and calibrators shall undergo certified laboratory calibration conformance testing at least once a year. The calibration certificate shall be submitted to the Engineer as specified in paragraph 1.03.C.

E. The sound level meter shall be on-site and readily accessible at all times.

F. All noise monitoring equipment must be documented as being "Y2K Compliant" to avoid any problems associated with the year 2000 programming issues.

2.03 NOISE REDUCTION MATERIALS AND EQUIPMENT

A. Noise reduction materials may be new or used. Used materials shall be of a quality and condition to perform their designed function.

B. Noise reduction equipment and materials may include, but not be limited to:

1. Shields, shrouds, or intake and exhaust mufflers.

2. Noise-deadening material to line hoppers, conveyor transfer points, storage bins, or chutes.

3. Noise barriers using materials consistent with the Temporary Noise Barrier materials specified in Article 2.04 of this Section.

4. Noise curtains using materials consistent with the Noise Control Curtains materials specified in Article 2.06 of this Section.

C. All equipment with backup alarms operated by the Contractor, vendors, suppliers, and subcontractors on the construction site shall be equipped with either audible self-adjusting ambient-sensitive backup alarms or manually-adjustable alarms. The ambient-sensitive alarms shall automatically adjust to a maximum of 5 dBA over the surrounding background noise levels. The manually-adjustable alarms shall be set at the lowest setting required to be audible above the surrounding noise. Installation and use of the alarms shall be consistent with the performance requirements of the current revisions of Society of Automotive Engineering (SAE) J994, J1446, and OSHA regulations, and as described in an Exhibit at the end of Division II Special Provisions.

D. All equipment used on the construction site, including jackhammers and pavement breakers, shall have exhaust systems and mufflers that have been recommended by the manufacturer as having the lowest associated noise.

E. The local power grid shall be used wherever feasible to limit generator noise. No generators larger than 25 KVA shall be used and, where a generator is necessary, it shall have maximum noise muffling capability and meet the noise emission limits specified in Table 2.

2.04 TEMPORARY NOISE BARRIERS

A. Temporary barriers shall be constructed of 3/4-inch Medium Density Overlay (MDO) plywood sheeting, or other material of equivalent utility and appearance having a surface weight of 2 pounds per square foot or greater. The temporary noise barriers shall have a Sound Transmission Class of STC-30, or greater, based on certified sound transmission loss data taken according to ASTM Test Method E90.

B. The temporary barriers shall be lined on one side with glass fiber, mineral wool, or other similar noise curtain type noise-absorbing material at least 2-inches thick and have a Noise Reduction Coefficient rating of NRC-0.85, or greater, based on certified sound absorption coefficient data taken according to ASTM Teat Method C423.

C. The materials used for temporary barriers shall be sufficient to last through the duration of construction for this Contract, and shall be maintained in good repair.

D. Construction Details

1. Barrier panels shall be attached to support frames constructed in sections to provide a moveable barrier utilizing the standard "Temporary Precast Concrete Median Barrier" for the Project, as shown on Standard Drawing SD-H-401 and SD-H-403 for Construction Barricade, or other supports designed to withstand 80 mph wind loads plus a 30 percent gust factor.

2. When barrier units are joined together, the mating surfaces of the barrier sides shall be flush with each other. Gaps between barrier units, and between the bottom edge of the barrier panels and the ground, shall be closed with material that will completely fill the gaps, and be dense enough to attenuate noise.

3. The barrier height shall be designed to break the line-of-sight and provide at least a 5 dBA insertion loss between the noise producing equipment and the upper-most story of the receptor(s) requiring noise mitigation. If for practicality or feasibility reasons, which are subject to the review and approval of the Engineer, a barrier can not be built to provide noise relief to all stories, then it must be built to the tallest achievable height.

E. Prefabricated acoustic barriers are available from various vendors. An equivalent barrier design can be submitted as specified in paragraph 1.03.G in lieu of the plywood barrier described above.

2.05 ACOUSTICAL BARRIER ENCLOSURES

A. Materials

1. The acoustical barrier enclosure shall consist of durable, flexible composite material featuring a noise barrier layer bonded to sound-absorptive material on one side.

2. The noise barrier layer shall consist of rugged, impervious material with a surface weight of at least one pound per square foot. The sound absorptive material shall include a protective face and be securely attached to one side of the flexible barrier over the entire face.

3. The acoustical material used shall be weather and abuse resistant, and exhibit superior hanging and tear strength during construction. The material shall have a minimum breaking strength of 120 lb/in. per FTMS 191 A-M5102 and minimum tear strength of 30 lb/in. per ASTM D117. Based on the same test procedures, the absorptive material facing shall have a minimum breaking strength of 100 lb/in. and a minimum tear strength of 7 lb/in.

4. The acoustical material shall be corrosion resistant to most acids, mild alkalies, road salts, oils, and grease.

5. The acoustical material shall be fire retardant and be approved by the City of Boston Fire Department prior to procurement. It shall also be mildew resistant, vermin proof, and non-hygroscopic.

6. The acoustical material shall have a Sound Transmission Class of STC-25 or greater, based on certified sound transmission loss data taken according to ASTM Test Method E90. It shall also have a Noise Reduction Coefficient rating of NRC-0.70 or greater, based on certified sound absorption coefficient data taken according to ASTM Test Method C423.

7. The Contractor shall submit the name of the manufacturer, properties of the material to be furnished, and two one-foot square samples to the Engineer for review prior to submittal of design and detailed engineering as specified in paragraph 1.03.G.

B. Construction Details

1. The acoustical barrier enclosure shall be designed similar to the example shown in Exhibit II-C, "Construction Noise Control Specification and Guidelines".

2. The acoustical material shall be installed in vertical and horizontal segments with the vertical segments extending the full enclosure height. All seams and joints shall have a minimum overlap of 2 inches and be sealed using double grommets. Construction details shall be performed according to the manufacturer's recommendations.

3. The Contractor shall be responsible for the design, detailing, and adequacy of the framework and supports, ties, attachment methods, and other appurtenances required for the proper construction of the acoustical barrier enclosure.

4. The design and details for the acoustical noise barrier enclosure framework and supports shall be prepared and stamped by a Registered Professional Engineer licensed in the Commonwealth of Massachusetts. The Contractor shall submit the design and detailed engineering drawings to the Engineer as specified in paragraph 1.03.G.

2.06 NOISE CONTROL CURTAINS

A. Materials

1. The noise control curtain shall consist of durable, flexible composite material featuring a noise barrier layer bonded to sound-absorptive material on one side. The noise barrier layer shall consist of a rugged, impervious material with a surface weight of at least one pound per square foot. The sound absorptive material shall include a protective face and be securely attached to one side of the flexible barrier over the entire face.

2. The noise curtain material used shall be weather and abuse resistant, and exhibit superior hanging and tear strength during construction. The curtain’s noise barrier layer material shall have a minimum breaking strength of 120 lb/in. per FTMS 191 A-M5102 and minimum tear strength of 30 lb/in. per ASTM D117. Based on the same test procedures, the noise curtain absorptive material facing shall have a minimum breaking strength of 100 lb/in. and a minimum tear strength of 7 lb/in.

3. The noise curtain material shall be corrosion resistant to most acids, mild alkalies, road salts, oils, and grease. It also shall be mildew resistant, vermin proof, and non-hygroscopic.

4. The noise curtain material shall be fire retardant and be approved by the City of Boston Fire Department prior to procurement.

5. The noise control curtain shall have a Sound Transmission Class of STC-30 or greater, based on certified sound transmission loss data taken according to ASTM Test Method E90. It shall also have a Noise Reduction Coefficient rating of NRC-0.85 or greater, based on certified sound absorption coefficient data taken according to ASTM Test Method C423.

6. The Contractor shall submit the name of the manufacturer, properties of the material to be furnished, and two one-foot square samples to the Engineer for review prior to submittal of the design and detailed engineering drawings as specified in paragraph 1.03.G.

B. Construction Details

1. The noise control curtains shall be designed such as described in an Exhibit at the end of Division II Special Provisions, "Construction Noise Control Specification and Guidelines." The curtains shall be secured above, at the ground, and at intermediate points by framework and supports designed to withstand 80 mph wind loads plus a 30 percent gust factor.

2. The curtains shall be installed in vertical and horizontal segments with the vertical segments extending the full curtain height to the ground. All seams and joints shall have a minimum overlap of 2 inches and be sealed using Velcro or double grommets spaced 12 inches on center. Curtains shall be fastened to framework and guardrails with wire cable 12 inches on center. Construction details shall be performed according to the manufacturer's recommendations.

3. The curtain height shall be designed to break the line-of-sight and provide at least a 5 dBA insertion loss between the noise producing equipment and the upper-most story of the receptor(s) requiring noise mitigation. If for practicality or feasibility reasons, which are subject to the review and approval of the Engineer, a curtain system can not be built to provide noise relief to all stories, then it must be built to the tallest achievable height.

4. The Contractor shall be responsible for the design, detailing, and adequacy of the framework and supports, ties, attachment methods, and other appurtenances required for the proper installation of the noise control curtains.

5. The design and details for the noise control curtains framework and supports shall be prepared and stamped by a Registered Professional Engineer licensed in the Commonwealth of Massachusetts. The Contractor shall submit the design and detailed engineering drawings to the Engineer as specified in paragraph 1.03.G.

CONSTRUCTION METHODS

3.01 NOISE MONITORING METHODS

A. General

1. The sound level meter and the acoustic calibrator shall be calibrated and certified annually by the manufacturer or other independent certified acoustical laboratory. The sound level meter shall be field calibrated using an acoustic calibrator, according to the manufacturer's specifications, prior to and after each measurement.

2. All measurements shall be performed using the A-weighting network and the "slow" response of the sound level meter.

3. The measurement microphone shall be fitted with an appropriate windscreen, shall be located 5 feet above the ground, and shall be at least 5 feet away from the nearest acoustically-reflective surface.

4. Noise monitoring shall not be performed during precipitation or when wind speeds are greater than 15 mph, unless the microphone is protected in such a manner as to negate the acoustic effects of rain and high winds.

B. Background Noise Monitoring

1. Background noise measurements (in dBA, slow) shall be collected for at least 24 hours over two non-consecutive days Monday through Saturday and one Sunday at noise monitoring receptor locations as specified in paragraph 1.06.B.1 prior to the start of construction. Background noise measurements should be performed in the absence of any contributing construction noise for each of the noise monitoring receptor locations identified in Table 3 and Figure 1 of this Section. Background noise L10 levels shall be arithmetically averaged into single L10 levels defining the background noise for daytime (7 AM - 6 PM), evening (6 PM - 10 PM), and nighttime (10 PM - 7 AM) time frames, respectively.

(Background noise measurements for each of the noise monitoring receptor locations identified in Table 3 and Figure 1 have already been collected for this contract and are furnished by the Engineer in Table 5 of this Section.)

C. Construction Noise Monitoring

1. Noise level measurements shall be taken at each noise-sensitive location during ongoing construction activities at least once each week during the applicable daytime, evening, and nighttime period. All other noise monitoring locations as specified in paragraph 1.06.B.1 shall be measured at least once each week during the daytime period.

2. The time period for each noise measurement shall be 20 minutes.

3. Construction noise measurements shall coincide with daytime, evening, and nighttime periods of maximum noise-generating construction activity, and shall be performed during the construction phase or activity that has the greatest potential to exceed noise level limitations as specified in Article 1.04 of this Section. Compliance noise measurements for the noise limits in Table 1 shall be performed at a point on a given lot-line which is the closest to the construction activity.

4. If, in the estimation of the person performing the measurements, outside sources contribute significantly to the measured noise level, the measurements shall be repeated with the same outside source contributions when construction is inactive to determine the ambient noise level contribution.

5. All measurements shall be taken at the affected lot-line. In situations where the Work site is within 50 feet of a lot-line, the measurement shall be taken from a point along the lot-line such that a 50 foot distance is maintained between the sound level meter and the construction activity being monitored.

6. Up to four 24-hour noise monitors shall be maintained at the lot-line of noise receptor locations and shifted among locations corresponding to construction activity as directed by the Engineer. These monitors shall be capable of recording the Lmax and L10 values in 20-minute intervals over 24-hour periods. These monitors shall be durable and enclosed in weather resistant cases, and located in a manner that will prevent vandalism. The data shall be downloaded and submitted as specified by paragraph 1.03.E.

3.02 REPORTING

A. Background, construction, and complaint response noise data shall be recorded on the Noise Measurements Report Form provided in Figure 4. The type of measurement shall be noted on the form.

B. 24-hour noise measurements shall be plotted graphically showing L10 and Lmax noise levels vs time along with appropriate lot-line criteria limits (from Tables 1 and 5) for daytime, evening, and nighttime periods.

C. Provide a sketch or diagram for the exact location of the noise measurement on the back of Figure 4. Include the location and distance of the noise measurement in relationship to the noise monitoring location specified in paragraph 1.06.B.1.

D. During construction and complaint response monitoring, all construction equipment operating during the monitoring period shall be identified and the location sketched on the back of Figure 4. The sketch shall include the distance between the noise measurement location and the construction equipment.

E. All activities occurring while performing noise measurements shall be noted in the "Field Notes" area of Figure 4. For example, "auger banging on ground to clean soil from threads" or "heavy traffic passing near the sound level meter." In addition, any noise level of 85 dBA or greater requires an explanation.

3.03 NOISE REDUCTION METHODS

A. The Contractor shall use all reasonable efforts to implement noise reduction methods listed below to minimize construction noise emission levels and as described or specified under Limiting Unnecessary Construction Noise in an Exhibit at the end of Division II Special Provisions. Noise reduction methods shall include, but not be limited to:

3.04 TEMPORARY NOISE BARRIERS

1. Use of: 1) concrete crushers or pavement saws for concrete deck removal, demolitions, or similar construction activity; 2) pre-auguring pile holes to reduce the duration of impact or vibratory pile driving; 3) tie to local power grid to reduce the use of generators.

2. Attaching: 1) intake and exhaust mufflers, shields, or shrouds; 2) noise-deadening material to inside of hoppers, conveyor transfer points, or chutes.

3. Maintaining: 1) equipment mufflers and lubrication; 2) precast decking or plates to avoid rattling; 3) surface irregularities on construction sites to prevent unnecessary noise.

4. Limiting: 1) the number and duration of equipment idling on the site; 2) the use of annunciators or public address systems; 3) the use of air or gasoline-driven hand tools.

5. Configuring, to the extent feasible: 1) the construction site in a manner that keeps loud equipment and activities as far as possible from noise-sensitive locations; 2) barrels or signage to detour traffic away from plated trenches.

6. Scheduling of construction events and limiting usage times to minimize noise, especially during nighttime hours and near sensitive abutters.

7. Erecting noise barriers and/or noise curtain systems to intervene between the noise source and the noise receptor locations.

8. Minimizing noise from the use of backup alarms using measures that meet OSHA regulations. This includes 1) use of self-adjusting ambient-sensitive backup alarms, 2) manually-adjustable alarms on low setting, 3) use of observers, 4) scheduling of activities so that alarm noise is minimized, 4) construction site access should be designed such that delivery and dump trucks move through the site in a forward manner without the need to back up.

9. Using only variable message and sign boards that are solar powered or connected to the local power grid.

A. General

1. The Contractor shall erect temporary noise barriers to mitigate construction noise at locations specified in the Noise Control Plan or as directed by the Engineer.

2. The temporary noise barriers shall be readily moveable so that they may be re-positioned, as necessary, to provide noise abatement for non-stationary, as well as stationary, processes.

B. Installation, Maintenance, and Removal

1. The barriers shall be installed such that the noise-absorptive surfaces face the construction noise source.

2. The Contractor shall maintain the temporary noise barriers and repair all damage that occurs, including, but not limited to, keeping barriers clean and free from graffiti and maintaining structural integrity. Gaps, holes, and weaknesses in the barriers, and openings between or under the units, shall be repaired promptly or replaced by the Contractor with new material.

3. The Contractor shall remove and dispose of the temporary noise barriers at the end of the Contract or sooner at the direction of the Engineer.

3.05 EQUIPMENT NOISE CERTIFICATION

A. General

1. For each piece of equipment meeting the requirements of paragraph 1.08.A of this Section, complete an Application for Certificate of Equipment Noise Compliance (Figure 5), which shall be signed by the Acoustical Engineer.

2. The equipment identification number used for certification shall be consistent with the identification number used in the Noise Control Plan (Figure 2).

B. Test Procedures for Construction Equipment

1. All engine-powered equipment shall be operated at high idle (maximum governed rpm) under full-load condition during the test.

2. Portable and mounted impact devices, such as hoe-rams and jackhammers, shall be tested during the first day of actual operation at the construction site under maximum load conditions as rated by the equipment manufacturer.

3. Pile-driving equipment shall be tested under maximum load conditions as rated by the manufacturer.

4. All noise monitoring equipment specified in Article 2.02 of this Section shall have a current certificate of calibration sticker affixed to it.

5. An acoustic calibrator of the type recommended by the sound level meter manufacturer shall be used prior to and after all measurements.

6. The noise level measurements shall be for a minimum period of 1 minute.

7. If possible, measurements shall be made at 50 feet ± 2 feet from the front, rear, and right and left sides of the equipment, at a height of 5 feet above ground level.

8. Measurements made at less than 50 feet, due to space limitations at the test site, shall be reduced by the values given in Table 4 to estimate the 50 foot noise level.

9. When confirmatory noise level testing is requested by the Engineer, the Contractor shall locate and operate the equipment as directed by the Engineer at the designated site so as to facilitate recording of the noise level by the Contractor.

C. Compliance

1. If the Lmax noise levels (in dBA, slow) obtained during the tests exceed those specified in Table 2, the Contractor shall promptly modify or alter such equipment, or substitute other equipment, and retest the equipment to show compliance with the noise level requirements.

2. Upon compliance, the Contractor shall submit the Equipment Noise Certificates provided in Figure 5 of this Section to the Engineer for review, approval, and recording as specified in paragraph 1.03.F.

3. The Certificate of Equipment Noise Compliance will remain valid for a period of 6 months only. Delays caused by the certification rejection, and time lost in mitigating the rejected equipment or finding alternate acceptable equipment, shall not be a basis for any monetary or time delay claims, or for avoidance of late completion penalties.

3.06 COMPLAINT PROCEDURE

A. The objective of the complaint procedure is to ensure that public and agency complaints are addressed and resolved consistently and expeditiously.

B. If the Contractor receives a complaint regarding construction noise, the Contractor shall immediately notify the Engineer and the Interim Operations Center (IOC) or successor to the IOC.

C. Upon receipt or notification of a noise complaint from the Engineer, the Contractor shall promptly perform noise measurements at the complainant's location during activities representative of the offending operation. The noise measurements shall be performed using equipment and methods as specified in Articles 2.02 and 3.01 and reported as specified in Article 3.02 of this Section. The complaint response noise measurements shall be immediately submitted to the Engineer as specified in paragraph 1.03.E of this Section.

D. In the event that the measured noise level exceeds allowable limits as specified in Article 1.04 of this Section, or is resulting in nuisance conditions, the Contractor shall immediately use noise reduction materials and methods such as, but not limited to, those described in Article 3.03 to reduce noise levels or to alleviate the nuisance conditions.

3.07 ACOUSTICAL BARRIER ENCLOSURES

A. General

1. The Contractor shall erect acoustical barrier enclosures to mitigate construction noise at locations specified in the Noise Control Plan as required in Article 1.07, construction drawings, or as directed by the Engineer.

2. The acoustical barrier enclosures shall be readily moveable so that they may be repositioned, as necessary, to provide noise abatement for non-stationary equipment (e.g., jackhammers, chain saws, compressors).

B. Installation, Maintenance, and Removal

1. The acoustical enclosure shall be installed such that the noise-absorptive surfaces face the construction noise source.

2. The Contractor shall maintain the acoustical barrier enclosures and repair all damage that occurs, including, but not limited to, keeping barriers clean and free from graffiti and maintaining structural integrity. Gaps, holes, and weaknesses in the acoustical enclosure, and openings between or under the panels, shall be repaired promptly or replaced by the Contractor with new material. Construction Work shall not proceed until such repairs are made.

3. The Contractor shall remove and dispose of the acoustical enclosure at the end of the Contract or sooner at the direction of the Engineer.

3.08 NOISE CONTROL CURTAINS

A. General

1. The Contractor shall erect noise control curtains to mitigate construction noise at locations specified in the Noise Control Plan as required in Article 1.07, construction drawings, or as directed by the Engineer.

2. Noise control curtains shall particularly be used for short-term operations (e.g., less than 3 months), or where vehicular or pedestrian access is required during the day, or as directed by the Engineer.

B. Installation, Maintenance, and Removal

1. The noise control curtains shall be installed without any gaps such that the sound-absorptive side faces the construction activity to be shielded. The curtains shall be supported by the existing elevated Expressway, ramps, or other methods identified in the Noise Control Plan.

2. The Contractor shall maintain the noise control curtains and repair all damage that occurs, including, but not limited to, keeping barriers clean and free from graffiti and maintaining structural integrity. Gaps, holes, and weaknesses in the noise control curtains, and openings between or under the panels, shall be repaired promptly or replaced by the Contractor with new material. Construction Work shall not proceed until such repairs are made.

3. The Contractor shall remove and dispose of the noise control curtains at the end of the Contract or sooner at the direction of the Engineer.

COMPENSATION

4.01 METHOD OF MEASUREMENT

A. The Noise Monitoring Plan and first Noise Control Plan will be considered incidental to Mobilization (Section 748.001).

B. The 6-month Noise Control Plans, equipment certifications, and complaint response and weekly construction noise monitoring reports will be considered incidental to the Construction.

C. Temporary noise barriers installed per Article 3.04 of this Section will be measured by surface area of one face of the noise barrier wall with no additions for bracing, supports, and other such projections.

D. Acoustical barrier enclosures constructed per Article 3.07 of this Section will be measured by surface area of one face of the acoustical enclosure with no additions for bracing, supports, and other such projections.

E. Noise control curtains installed per Article 3.08 of this Section will be measured by surface area of one face of the noise control curtains with no additions for bracing, supports, and other such projections.

4.02 BASIS OF PAYMENT

A. Payment for the Noise Monitoring Plan and first Noise Control Plan will be considered part of the payment for Mobilization.

B. Payment for the 6 month Noise Control Plans, equipment certifications, and complaint response and weekly construction noise monitoring reports will be considered part of the payment for related Construction.

C. Payment for temporary noise barriers installed per Article 3.04 of this Section will be at the Contract unit price per square foot, which shall be full compensation for constructing, providing, placing, maintaining, moving, and disposing of temporary noise barrier walls.

D. Payment for the acoustical barrier enclosures constructed per Article 3.07 of this Section will be at the Contract unit price per square foot, which shall be full compensation for constructing, providing, placing, maintaining, moving, relocating, and disposing of temporary acoustical barrier enclosure.

E. Payment for the noise control curtains installed per Article 3.08 of this Section will be at the Contract unit price per square foot, which shall be full compensation for constructing, providing, placing, maintaining, moving, relocating, and disposing of the noise control curtains.

4.03 PAYMENT ITEM

END OF TEXT FOR THIS SECTION

TABLES 1 - 5 AND FIGURES 1 - 5 FOLLOW

TABLE 1. CONSTRUCTION NOISE LOT- LINE LIMITS (b), (c), (d)

NOTES

(a) Noise from impact equipment is exempt from the L10 requirement, however is subject to a lot-line Lmax limit of 90 dBA.

(b) All measurements shall be taken at the affected lot-line. In situations where the work site is within 50 feet of a lot-line, the measurement shall be taken from a point along the lot-line such that a 50 foot distance is maintained between the sound level meter and the construction activity being monitored.

(c) Lot-line noise limits shall apply to all points along the receptor’s lot-line.

(d) L10 noise readings are averaged over 20 minute intervals. Lmax noise readings occur instantaneously.

TABLE 2. CONSTRUCTION EQUIPMENT 50 FOOT NOISE EMISSION LIMITS (a), (b)

NOTES:

(a) Measured at 50 feet from the construction equipment, with a "slow" (1 sec.) time constant.

(b) Noise limits apply to total noise emitted from equipment and associated components operating at full power while engaged in its intended operation.

(c) "Impact" equipment is assumed to produce separate discernable sound pressure maxima.

(d) "Acoustic Usage Factor" represents the percent of time that equipment is assumed to be running at full power while working on site

TABLE 3. NOISE MONITORING LOCATIONS (See Also Figure 1)

TO BE DEVELOPED SPECIFICALLY FOR EACH CONTRACT

TABLE 4. ADJUSTMENTS FOR EQUIPMENT NOISE MEASUREMENTS AT LESS THAN 50 FEET

TABLE 5. BACKGROUND NOISE LEVELS AND CORRESPONDING LOT-LINE NOISE CRITERIA

TO BE DEVELOPED SPECIFICALLY FOR EACH CONTRACT

Notes:

Daytime is defined as 7 AM to 6 PM

Evening is defined as 6 PM to 10 PM

Nighttime is defined as 10 PM to 7 AM

n/a indicates that data was either not available or criteria limits do not apply

INSERT CONTRACT- SPECIFIC MAP

INSERT CONTRACT- SPECIFIC MAP

FIGURE 1. SITE MAP & NOISE MONITORING LOCATIONS

NOISE CONTROL PLAN

(duplicate as needed)

PART A: EQUIPMENT INVENTORY

Contract No.: _______________ Contract Name: _______________________Contractor: ___________________

Site: ______________________ Date: ________________ Resubmit every 6 months

(ATTACH SITE SKETCH)

FIGURE 2. NOISE CONTROL PLAN FORM - PART A

NOISE CONTROL PLAN

(duplicate as needed)

PART B: PREDICTED NOISE LEVELS

Contract No.: ___________________________ Contract Name: _________________________

Contractor: _____________________________ Site: __________________________________

Date: __________________________________ Land Use: _____________________________

Resubmit every 6 months

CALCULATIONS - attach additional sheet(s) as needed

FIGURE 3. NOISE CONTROL PLAN FORM - PART B

Central Artery / Tunnel Project

CONTRACT NO(S):__________________________ DATE: _____________________________________ TIME:__________________________________ Hrs (0000 Hrs - 2359 Hrs)

NOISE MEASUREMENTS REPORT FORM

MEASURED BY:___________________________________ OF: ________________________________________

(COMPANY)

MONITORING ADDRESS: __________________________________________________________________

(PROVIDE SKETCH ON BACK)

LOCATION NO:__ N - ____________ WIND SPEED:_____________ MPH DIRECTION: ________________

LOCATION OF SOUND LEVEL METER: (NO CLOSER THAN 50 FEET FROM EQUIPMENT AND 5 FEET FROM REFLECTIVE SURFACE)

MONITORING WAS CONDUCTED:__________FEET FROM EQUIPMENT(___________________________)

(TYPE(S); LEAVE BLANK FOR BASELINE)

LAND USE: o RESIDENTIAL/INSTITUTIONAL o BUSINESS/RECREATIONAL o INDUSTRIAL

SOUND LEVEL METER: MAKE AND MODEL:_______________________________________________

DURATION OF MEASUREMENT:______________________

CALIBRATION LEVEL:_______________________________

(*) indicates required noise measurement data

CHECK ONE OF THE FOLLOWING

o ONGOING CONSTRUCTION o POST-CONSTRUCTION:_____________________o BASELINE CONDITIONS

(CONTRACT)

(COMPLETE ALL THAT APPLY BELOW)

ACTIVE CONTRACT(S):_____________________________________________________________________

COMPLAINT RESPONSE:____________________________________________________________________

ABATEMENT FOLLOW UP:__________________________________________________________________

FIGURE 4. NOISE MEASUREMENTS REPORT FORM

APPLICATION FOR CERTIFICATE OF EQUIPMENT NOISE COMPLIANCE

Contractor Name:____________________________________________________________________________

Contract Name & Number:_____________________________________________________________________

Equipment Type:_____________________________________________________________________________

Manufacturer & Model NO.:____________________________________________________________________

Identification Number:_________________________________________________________________________

Rated Power & Capacity:______________________________________________________________________

Operating Cond. During Test:____________________________________________________________________

Measured Lmax Noise Levels and Distance:

Right Side:_________________ dBA(SLOW), at__________________ feet

Left Side:__________________ dBA(SLOW), at__________________ feet

Adjusted Lmax Noise Levels at 50 Feet:

Right Side:_________________ dBA(SLOW).

Left Side:__________________ dBA(SLOW).

Equipment Noise Emission Limit (Table 2): _____________ dBA(SLOW)

If equipment noise level exceeds maximum value allowed, indicate action taken to achieve compliance:

_____________________________________________________________________________________

_____________________________________________________________________________________

ACOUSTICAL ENGINEER

Name, Address & Phone No.__________________________________________________________

ACOUSTICAL ENGINEER

Authorized Signature: _____________________________________Date: ______________________

CONTRACTOR'S CONCURRENCE

Authorized Signature: _____________________________________Date: ______________________

ENGINEER'S CONCURRENCE

Authorized Signature: _____________________________________Date:______________________

FIGURE 5. EQUIPMENT NOISE LEVEL DATA REPORTING FORM