What drives the cost of a noise survey

This page explains what the rules and common practice call for. Every site is different, and what a survey or a filing needs at your facility is something we work out with you after we see it.

Much of what is published about noise survey pricing comes from the UK, where the Control of Noise at Work Regulations apply. Those regulations use different trigger levels than OSHA, and a 3 decibel exchange rate where OSHA uses 5 decibels. (The exchange rate is the number of added decibels that cuts the allowed exposure time in half.) As a result, those price figures do not carry over to a US survey.

This guide covers what drives the price of a survey run to OSHA's noise standard, including the one scheduling choice that moves the price more than anything else.

What you're paying for

1. Field time

Field time is the largest cost. Workers wear noise dosimeters, which go on before the shift starts and come off after it ends, and someone has to be on site for both. In between, that person conducts the area survey.

Most single-shift surveys take 1 field day. Plants that run 2 or 3 shifts need either more days or a return visit, because you cannot learn what second shift is exposed to by monitoring first shift. Field days are the unit that almost everything else is priced around.

2. Number of dosimeters

Unlike air sampling, there is no laboratory cost for each sample, because the dosimeter gives the result directly. That makes a noise survey a good deal less expensive than air monitoring, and it means an additional dosimeter adds little cost on a visit you are already paying for.

The practical advice follows from that: if you're already paying for the field day, measure more people. More dosimeters make the result for a similar exposure group (SEG, workers who do the same job the same way) more precise, because precision improves with the square root of the number of samples. Going from 6 dosimeters to 12 cuts the uncertainty in that result (the standard error) by about 30%. That is a real gain for a small addition to the bill, whereas going from one field day to two nearly doubles it.

3. Area survey and noise map

Sound level readings taken across a documented grid give you the map you will use to plan noise controls and decide where signs go. The price depends on the square footage of the plant and the complexity of the layout.

4. Octave band analysis

Octave band analysis shows how the noise is distributed across frequencies, from low to high. It is an add-on. You need it when you are planning engineering noise controls, and when you select hearing protectors by the long method, which works frequency band by frequency band. You can skip it if you only need a record documenting compliance with the standard, but not if you intend to actually reduce the noise. → Octave band analysis

5. Report

The report should give you:

• Results by worker and by exposure group
• A sound level map
• An evaluation of whether your hearing protectors provide enough attenuation
• What your results require you to do

→ What a noise survey report should contain

Three sizes of job, and what sets them apart

A small machine shop, single shift. The shop has 18 workers on 1 shift and needs an initial survey to show where it stands under the standard. That takes 1 field day, roughly 8 dosimeters, an area survey and sound level map, and a report. This is the smallest version of the job that is still defensible.

A fabrication plant across two shifts, with planning for noise controls. The plant has 70 workers on 2 shifts and wants octave band analysis on 3 problem areas. That takes 2 field days and around 20 dosimeters split across the shifts, and it produces a noise map and a report that recommends controls, not only results. This is roughly double the first job, and the second shift drives most of the difference.

Noise and air monitoring on one trip. Picture an aerospace supplier with welding fume and hexavalent chromium exposures, along with noise. That takes 2 field days shared across both surveys, and it includes air samples with laboratory analysis, 12 dosimeters and one combined report. Travel is paid once, not twice.

That third job is the one worth planning for. The dosimeters go on the same workers, during the same shift, on the same visit as the air sampling pumps. Scheduling the two surveys separately means paying twice for mobilization, travel and setup, and you get no more information for it. → Air monitoring surveys

What moves the price

Up:

• More than one shift. This is the most common cost driver by far, because second shift is genuinely different and you cannot infer its exposures from first shift.
• More exposure groups. The count depends on the number of distinct jobs, not on headcount.
• Plant size, for the area survey portion. A 300,000 square foot plant takes considerably longer to grid than a 20,000 square foot shop.
• Octave band analysis, where required.
• Extended shifts. For 10- and 12-hour operations, the 8-hour time-weighted average (TWA) has to be calculated against the actual shift length, and there is more shift for someone to sit through.
• Out-of-state travel.
• Noise control design work, beyond measuring the noise.

Down:

• Combining it with air sampling. This is the largest single saving available.
• Good preparation. That means a floor plan, worker counts by job, shift schedules, an equipment list and data from previous surveys.
• A compliance-only survey, if you genuinely don't need to plan noise controls yet.
• Monitoring more people on a visit you're already paying for. This lowers the cost for each unit of confidence, which is the number that really matters.

The cost that arrives after the survey

A noise survey that comes back over the action level is not a one-time expense. It's the start of a hearing conservation program.

For noise, the action level is an 8-hour TWA of 85 decibels (dBA). Once workers are at or above it, OSHA's noise standard requires all of the following:

• Audiometric testing. A baseline audiogram within 6 months of first exposure, then an audiogram every year. This cost recurs for each worker, with no end date.
• Hearing protectors provided at no cost, with a variety to choose from.
• Annual worker training.
• Recordkeeping. Keep noise exposure measurements for 2 years, and keep audiometric test records for as long as the worker is employed.
• Repeat monitoring whenever production, process, equipment or controls change enough either to bring more workers over the action level or to make the hearing protection in use inadequate.

The survey is a one-time cost, while the program is a cost every year. Over any reasonable period, the program is the larger of the two.

It is worth budgeting for the program before the results come back, not afterward. It is also worth knowing that engineering noise controls can take workers out of the program entirely, and the recurring cost goes with them.

When you may not need a survey

Some workplaces are clearly quiet, such as an office, light assembly, or a warehouse with no powered equipment near people. If that describes your workplace, you may not reach the monitoring trigger in OSHA's noise standard at all, and a formal survey may be premature.

If you are genuinely unsure, that is a short conversation, not a project. Describe your operation and we'll tell you whether you're in the range where this matters.