5.0 MEASUREMENT OF CONSTRUCTION NOISE (continued)

5.4 Measurement of Construction Operations

5.4.1 Establishing Measurement Locations and Periods

To the extent possible, measurement locations and time periods selected for the evaluation of noise generated by construction operations should be the same as those used to determine background or pre-construction noise levels. Such measurements are conducted in conformance with established measurement protocols, as previously discussed. Separate noise measurement protocols exist for measurement of individual pieces of construction equipment, and are discussed later in this section.

Most measurements of noise from construction activities are conducted in exterior locations. Depending upon how a particular controlling ordinance, regulation, or procedure is written, such measurements may be taken at different locations, including:

At the property line closest to the construction activity;
At a residence or other sensitive receptor; and
At the point of closest frequent human activity.

A noise analysis using a sound level meter in the back yard of a resident to establish pre-construction background noise levels.

Figure 5.17 Measurement near a residence (Photo #1286)

A noise analysis using a sound level meter is performed on an elevated deck extending off a nearby home; this is the area of frequent human use and is thus the receiver location.

Figure 5.18 Measurement on a raised deck (Photo #1285)

Many local ordinances specifically require consideration of noise to be addressed at the property line location, while some regulations are less definitive in terms of precise locations. Measurements taken at or near the actual residence are more easily converted to interior levels through application of building reduction factors.

A noise analysis using a sound level meter of pre-construction background sound levels at the property line; many noise ordinances consider property line sound levels.

Figure 5.19 Property line noise measurement (Photo #1290)

Figure 5.20 Noise measurement
inside church sanctuary (Photo #1284)

A noise analysis using a sound level meter inside a church sanctuary to establish pre-construction interior background sound levels; sanctuaries are special uses that may warrant special consideration.

On occasion, it may be necessary to take interior noise measurements to establish interior levels. Building noise reduction factors can be obtained by simultaneous exterior and interior measurements.

A noise analysis using a sound level meter in the courtyard outside a church sanctuary to establish pre-construction exterior background sound levels.

Figure 5.21 Noise measurement in courtyard outside church sanctuary (Photo #1130)

5.4.2 Determining Events/Activities to Measure

When it has been determined that an analysis of construction noise is required, consideration of particular events or activities associated with the project's construction is appropriate. Each project is typically evaluated individually considering the relationship of both stationary and mobile construction activities to sensitive adjacent receptors and considering the timing of construction activities in relation to activities occurring within the community. Several options that exist in terms of the measurement of construction operations are discussed below.

5.4.2.1 Measuring Entire Project Construction Noise

Ideally, the most accurate representation of a project's construction noise level at any given location would be obtained by extensive and/or continuous monitoring of noise levels from all construction operations at that location. For the limited complex projects where such monitoring has been performed, complex noise monitoring systems and/or programs have been employed^{ref009, ref082, and ref103}. Except for complex projects and projects where construction is of short duration and occurring within a limited project area, such monitoring is probably not practical based on timing, manpower, and equipment constraints.

5.4.2.2 Measuring an Entire Operation

Measuring an entire operation suggests that all activities associated with a particular construction operation are occurring in a relatively short timeframe. An example may be a paving operation that occurs in the vicinity of a particular home or neighborhood over a one-day period. In such a case, the collective noise generated from all components of the operation could be measured and compared to background levels and/or absolute noise level criteria. Evaluation and screening of the project's schedule of individual construction operations can be used to determine, in advance, which construction operations are likely to produce the greatest noise levels at a particular location. Emphasis can then be placed on monitoring the operations with the potential to create the highest noise levels at that location.

A highway re-alignment project near an existing highway where multiple construction activities are occurring simultaneously; due to the multitude of equipment, such as cranes, front end loaders, dump and cement mixing trucks, noise levels may be high and the entire operation could be measured

Figure 5.22 High concentration of activity, a good candidate for measuring an entire operation (Photo #462)

Since construction of a highway typically involves many different phases and operations, it is appropriate to consider the following operations and the sensitive receptors that could be potentially impacted by each operation:

Mobilization;
Demolition;
Clearing and grubbing;
Earthwork;
Structures and foundations;
Bridge Construction;
Grading for pavement base construction;
Paving; and
Cleanup.

5.4.2.3 Measuring Partial Operations

The evaluation and screening process used to determine the activities with the highest potential for construction noise impacts may identify specific portions of an operation that could warrant noise monitoring. For instance, a bridge construction project, blasting for foundation construction, pile driving activities, or rock excavation operations may be identified as having significantly greater potential for noise impacts than other activities such as forming, concrete pours, rod setting, etc. Obviously, each activity may have its own established noise level limit that may need to be considered in this process.

An explosion with smoke and debris flying from a blasting operation near a low volume roadway; blasting is an extremely noisy activity.

Figure 5.23 Blasting operation (Photo #1309)

A crane with pile driving hammer with a nearby residence in the background. Pile driving is an extremely noisy activity.

Figure 5.24 Pile driving operation (Photo #856)

A dump truck awaits rocks from a loader while another dump truck waits in line; rock excavation is a noisy activity.

Figure 5.25 Rock excavation operation (Photo #981)

5.4.2.4 Measuring Indirect Noise Effects

Construction projects often create activities that extend beyond the project limits. It is essential to consider the potential for noise effects of such activities on adjacent sensitive receptors, particularly those located in communities particularly sensitive to noise. Examples of such activities include:

Trucks supplying material (stone, concrete, steel, etc.) to the project;

A heavy truck designed for oversized loads transports long and wide steel beams on a residential road.

Figure 5.26 Steel beam transported adjacent to residences (Photo #1208)

Trucks hauling excess material from the project;

A dump truck hauling excess material from a construction site transports its cargo on a local roadway with automobile traffic present and residents adjacent to the roadway.

Figure 5.27 Dump truck on local roadway (Photo #1179)

Activity associated with off-site operations such as concrete batch plants, waste areas, wetland creation sites, material storage areas, etc.; and

A concrete batch plant operation uses several pieces of stationary equipment along with an arriving cement mixing truck; a temporary wooden noise barrier blocks the operation noise for a community to the right.

Figure 5.28 Concrete batch plant operation; shown here with temporary noise barrier for community to the right (Photo #322)

Several bulldozers form a stockpile of fill material while an unloaded dump truck exits the construction site. The fill material is placed between the construction equipment and a residence.

Figure 5.29 Stock pile operation in vicinity of residence (Photo #1258)

Effects of traffic detoured or rerouted due to construction activities.

A highway separated by a jersey barrier from an adjacent highway widening project is congested with the traffic diverted because of the project.

Figure 5.30 Communities can be affected by traffic diverted by construction activities (Photo #1046)

5.5 Measurement of Equipment Noise

Compared to noise generated by construction operations, equipment noise levels can be measured under more controlled conditions. Standard measurement practices and techniques and acceptable limits (for certain projects) have been established for the measurement of noise from many specific types of construction equipment. Practices and techniques for the measurement of construction equipment noise levels on highway-related projects are described in Chapter 7 of Reference 006. Noise measurement procedures used in determining equipment noise levels that were ultimately incorporated into the RCNM program are described in Section 3.01 of Reference 023. In many cases, these protocols and limits account for the typical operational characteristics of the piece of equipment, such as stationary equipment (generators, pile drivers, jackhammers, compressors, etc.), mobile equipment (on-road trucks), and cyclical operating equipment (pans, graders, front end loaders, on-site truck operations, etc.).

An auger is mounted to a stationary piece of equipment thus becoming a stationary construction operation where the noise source doesn’t move.

Figure 5.31 Stationary construction operation (Photo #123)

A paver is transported to a construction site on a heavy truck with an oversized trailer.

Figure 5.32 On-road construction vehicle (Photo #1243)

The loading and dumping of fill, at a designated stock pile location, is a cyclical operation. This means it is both a mobile and stationary function that creates noise and both functions are performed in a timed pattern.

Figure 5.33 Construction vehicle involved in cyclical operation (Photo #1005)

5.6 Type of Noise Measurement Equipment and Systems

A wide variety of noise measurement equipment is currently available for use in the measurement of construction noise levels. Some examples of the range of such equipment include:

Type I and Type II sound level meters with a variety of data output options and with the ability to report noise levels for a variety of noise level descriptors;

Two Type I sound level meters are placed side-by-side for comparison. Both have a spherical windscreen protecting the microphone and both have many functions available on their touchpad.

Figure 5.34 Type I sound level meters (Photo #1296)

A Type II sound level meter with a cylindrical windscreen covering the microphone. This Type II meter has very few buttons on the touchpad, likely for ease of use.

Figure 5.35 Type II sound level meter (Photo #1297)

Permanent, continuous noise monitoring systems, with and without integrated video systems; and
Automated monitoring systems, with and without integrated video systems.

A permanently mounted automated wireless noise monitoring system is attached to the top of a telephone pole. Note the solar cell for power, an antenna and transmitter for sending data, and a microphone covered with a cylindrical windscreen.

Figure 5.36 Permanent automated wireless noise monitoring system; note solar cell, antenna, transmitter, and microphone (Photo #48)

The need obviously exists to tailor the type of equipment utilized to the complexity of the project and its construction noise monitoring requirements.

In performing valid construction noise measurements, the following factors should generally be considered:

Meeting ANSI S1.4 Standard for Type I or Type II accuracy;
Using an "integrating" sound level meter;
Ability to measure and display L_eq, L_max, and L_n;
Ability to measure A-weighted decibels;
Capable of measuring at slow and fast RMS response settings;
Ability of monitor to be calibrated in the field;
Use of a proper wind screen; and
Proper measurement locations as related to adjacent buildings, structures, and activities.

References to documents containing specific information related to the following topics include:

Types of measurement equipment^{ref 006};
History of measurement techniques^{ref001, ref006, and ref007};
Current construction noise monitoring state-of-the-art^ref006; and
Details related to complex noise monitoring systems and programs^{ref009 and ref103}.

5.7 Other Factors to Consider

In addition to the factors discussed above, other factors to consider in setting up a construction noise-monitoring program include:

Loss prevention techniques - protection and security issues related to noise measurement equipment, particularly if left unmanned;
Processing of measured data;
Manpower requirements;
Power requirements - electric, solar, etc.; and
Need to identify unique and unusual noise generating events.

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