Industrial Hygiene Assessment Services

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Puzzle light bulb representing insight ih consultings dedication to creative problem solving in industrial hygiene samplingInsight Defined

in·sight (/inˌsīt/)


the capacity to gain an accurate and deep intuitive understanding of a person or thing.

synonyms: perception, awareness, understanding, comprehension


Insight IH Consulting is dedicated to providing a greater understanding of your health and safety issues. We can provide innovative solutions that allow for better comprehension of the exposures present within a workplace environment, and can help guide you down the path of both compliance and corrective actions.

The Occupational Safety and Health Administration (OSHA) has established permissible exposure limits (PELs) for nearly 500 chemicals (Table Z-1Table Z-2, and Table Z-3).  These limits are subject to the rulemaking process, which means the interest of all involved parties are taken into consideration.  This process can become heavily political, as can be seen with the revised 1989 Air Contaminants standard, which updated many of the PELs, and was vacated three years later because certain legal requirements were not met in establishing risk.    As such, most of the original limits have not been updated since they were first instituted shortly after the adoption of the Occupational Safety and Health (OSH) Act of 1970.  (For reference, just 39% of households had a color television in 1970, and the median house price was $24,000).

Since OSHA cannot effectively update its exposure limits, several other organizations have stepped in a filled the void with advisory limits that are updated much more regularly, using the most current science.  The American Congress of Governmental Hygienists (ACGIH) has established threshold limit values (TLVs) for more than 700 chemicals.  The American Industrial Hygiene Associated (AIHA) has established Workplace Environmental Exposure Limits (WEELs) for hundreds of substances.  Likewise, the National Institute for Occupational Safety and Health (NIOSH) has established recommended exposure limits (RELs) for many substances.

We have significant experience in determining the applicable 8-hour time-weighted average (TWA), ceiling concentration, short-term exposure limit (STEL) for hundreds of commonly used industrial substances. Typically, the personal breathing zone concentrations are determine through a sampling train (pump, tube, media) or passive badge/monitor that is placed into the employee’s breathing zone for a specified duration. This normally is performed for a full 8-hour shift, but can involve shorter term samples, depending on the substance and use. The typical end product is a full report which documents observations, methodology, and results as they compared to applicable exposure limits. Call (262.347.6599) or email ( today.

OSHA has also set legal limits on noise exposure in the workplace. These limits are based on a worker’s time weighted average over an 8 hour day. With noise, OSHA’s permissible exposure limit (PEL) is 90 dBA for all workers for an 8 hour day. The OSHA standard uses a 5 dBA exchange rate. This means that when the noise level is increased by 5 dBA, the amount of time a person can be exposed to a certain noise level to receive the same dose is cut in half. Further, employers are required to implement a Hearing Conservation Program where workers are exposed to a time weighted average noise level of 85 dBA or higher over an 8 hour work shift. Hearing Conservation Programs require employers to measure noise levels, provide free annual hearing exams and free hearing protection, provide training, and conduct evaluations of the adequacy of the hearing protectors in use unless changes to tools, equipment and schedules are made so that they are less noisy and worker exposure to noise is less than the 85 dBA.

The best means of determining workplace noise levels is through the use of personal dosimeters which are place on the shoulder of employees and worn for the full work shift. We can also perform sound level surveys using a handheld sound level meter (and can process the results into a color contour map overlaying your facility layout). The typical end product is a full report which documents observations, methodology, and results as they compared to applicable exposure limits.

Mapping of an indoor workplace is very useful for determining the background concentrations that are present throughout a facility, and to identify weaknesses in engineering controls (ventilation, barriers, etc.) that could drive employee exposures. Rather than a compliance assessment, which is typically averaged over 8-hours, mapping is performed over a finite period of time, providing a snapshot of the facility conditions. To perform this, a real-time monitoring devices is typically located at potentially hundreds of locations for as little as a minute (depending on instrument response time). Readings are recorded and “mapped” onto a facility map. The subsequent patterns that emerge, coupled with worker exposure data and knowledge of the facility, can be instrumental in correcting problems and establishing a baseline to benchmark improvement projects.

A typical contaminant mapping job will consist of fixed area samples, multiple static background monitors, and a single portable monitor. We can complete most mapping activities in a single work shift. The end product will consist of a report documenting the workplace, multiple color contour maps of the measured concentrations overlaying the facility layout, and concentration graphs for the static monitors.

This type of monitoring involves real-time monitoring devices. Depending on the contaminant these can vary from aerosol monitors (for respirable dust and respirable silica) to photo-ionization detectors (benzene, toluene, and other solvents) to electro-chemical cells (carbon monoxide). Such studies are best performed with multiple meters to best identify masking factors (such as fugitive concentrations and upsets) and extraneous sources. This is truly an investigative process that follows the scientific method. The final work deliverable is obtained through statistical parsing of the collected data (which commonly consists of thousands of measurements) to correlate concentrations to work activities and processes. The information obtained is very useful to best direct engineering controls (which can be very costly) so that the install equipment provides the most benefit to employees.

Typically real-time monitoring is conducted simultaneously with full-shift personal breathing samples. Often multiple monitors will be utilized, to determine both personal and background concentrations at each targeted workstation. The end product consists of a detailed report with real-time concentration graphs, statistical breakdowns of the gathered data, results tables, and a description of the work activities and methodologies used.

Exhaust hoods, duct work, collectors, and blowers are all engineered systems that decay over time. Systems are changed without engineering input. Processes are removed and relocated. Exhaust features are damaged though production activities and forklifts. Supply systems have been deactivated or removed altogether. All can be contributing factors to decreased efficiencies within a ventilation system. When deficiencies develop, employee exposures often are impacted, as the system was likely installed to control generated contaminants. An excellent initial step in correcting high employee exposures is to bring ventilation systems back into a state where the developed concentrations can be effectively controlled. Defects can be identified through the mapping and root causes work described above, but further measurement and characterization of flow rates, velocities, and sizing of the system can also find action items that can greatly improve the indoor air quality when corrected.