Module 06 Respirators and airborne contaminants

Slide 1 Introduction

Respirators- Respirators protect us from airborne contaminants. Entertainment technologists wear respirators for personnel protection in scene shop, metal shop and paint shop. Workers should read the SDS to determine what type of PPE is appropriate for the materials they are handling.

Slide 2 Definition of airborne contaminants

One scientific description of airborne contaminants is a system of particles suspended in a gaseous medium, usually air.

Remember: In a working environment, once the particles are produced they can affect both the health of the worker and the environment.

In a person the tissues of the upper respiratory tract and lungs can be affected.

The outcome of the exposure depends on the solubility of the inhaled matter. Inhaled contaminants can cause tissue damage, disease, or a physical obstruction.

 

The question becomes; how serious are airborne contaminants?

One example of an airborne contaminant is silica dust. Crystalline silica is an important industrial material found abundantly in the earth’s crust. Quartz, the most common form of silica, is a component of sand, stone, rock, concrete, brick, block, and mortar. Materials containing quartz are found in a wide variety of workplaces.

Silica dust is hazardous when very small (respirable) particles are inhaled. These respirable dust particles can penetrate deep into the lungs and cause disabling lung diseases such as lung cancer, and kidney disease.[1]

Occupational exposure to respirable crystalline silica occurs when cutting, sawing, drilling, and crushing of concrete, brick, ceramic tiles, rock, and stone products. Occupational exposure also occurs in operations that process or use large quantities of sand, such as foundries used in the creation of glass, pottery and concrete products. OSHA estimates that more than 2.3 million workers in the United States are potentially exposed to dust containing crystalline silica with nearly 90% of those workers employed in the construction industry.

The silica dust may have little effect on the lungs but the particles are so small they can be absorbed into the bloodstream and carried to other organs or damage the blood itself.

The old OSHA silica standard was adopted decades ago and was now failing to protect workers. It allowed very high levels of exposure and has no requirements to train workers or monitor exposure levels.[2]

In 2014 a series of hears to discuss the dangers of silica dust were presented at the capital. As of this year new rules are in place. The Occupational Safety and Health Administration (OSHA) issued a final rule in an effort to curb exposure to respirable crystalline silica. The rule is comprised of two standards, one for Construction and one for General Industry and Maritime.

Key Provisions

• Reduces the permissible exposure limit (PEL) for respirable crystalline silica to 50 micrograms per cubic meter of air, averaged over an 8-hour shift.
• Requires employers to: use engineering controls (such as water or ventilation) to limit worker exposure to the PEL; provide respirators to limit exposure; limit worker access to high exposure areas; develop a written control plan, offer medical exams to highly exposed workers, and train workers on silica risks and how to limit exposures.
• Provides medical exams to monitor highly exposed workers and gives them information about their lung health.[3]

OSHA estimates that the rule will save over 600 lives and prevent more than 900 new cases of silicosis each year, once its effects are fully realized. The Final Rule is projected to provide net benefits of about $7.7 billion, annually.

 

Today we will be examining the common types of airborne contaminants

USDL OSHA list approximately 873 types of air contaminants with OEL ratings.

Slide 3 Gases

1. A formless fluid that can expand to fit any space. A gas has theability to diffuse, and has a tendency to become distributed uniformly throughout any container.
2. The example I picked is CO2: carbon dioxide is the principal product oxide of carbon formed from the combustion of hydrocarbon fuels. Carbon dioxide is the focus of public concern in recent years due to the increasing concentration of this gas in the atmosphere as a result of the combustion of fossil fuels.[4]

Slide 4 Vapor-  A gaseous form of a liquid

The gaseous state of a substance that is normally liquid or solid at room temperature, such as water that has evaporated into the air.

Vapor. A vapor is the gas form of a substance that can also exist as a liquid at normal pressure and temperature. Most organic solvents evaporate and produce vapors. Vapors can be inhaled into the lungs, and in some cases may irritate the eyes, skin, or respiratory tract. Some are flammable, explosive, and/or toxic.

Slide 5 Mist

Mist. A mist consists of liquid particles of various sizes which are produced by agitation or spraying of liquids. Mists can be hazardous when they are inhaled or sprayed on the skin. The spraying of pesticides and the machining of metals using metal working fluids are two examples of mists

 

Slide 6

Dust. A dust consists of small solid particles in the air or on surfaces. Dusts may be created when solids are pulverized or ground. Dusts may be hazardous because they can be inhaled into the respiratory tract. Larger particles of dust are usually trapped in the nose where they can be expelled, but smaller particles (respirable dust) can reach and may damage the lungs. Some, like lead dust, may then enter the bloodstream through the lungs. Some dusts, such as grain dust, may explode when they reach high concentrations in the air.

 

Slide 7 Fume

A fume consists of very small, fine solid particles in the air. which form when solid chemicals (often metals or plastics) are heated to very high temperatures, evaporate to vapor, and combine with oxygen. The welding or brazing of metal, for example, produces metal fumes. Fumes are hazardous because they are easily inhaled, and have a large surface area in contact with body tissues. Some metal fumes can cause occupational illnesses when Inhaled. Other metal fumes, such as lead, can cause poisoning.

 

Slide 8 Smoke

Created by burning natural substances such as wood

 

Slide 9 Fiber

Airborne asbestos fibers, when inhaled, can cause serious disease.  Many people who fabricated and installed asbestos-containing materials (ACM) died from occupational illnesses linked to their exposure to asbestos. Because of the hazards, Environmental Protection Agency (EPA) regulations now prohibit the manufacture and sale of most asbestos products. Exceptions include a few specialty products for which no suitable substitute material has been found.[5]

 

Slide 10 Particulate size

Respirable the smallest under discussion is under 10 microns- lungs sacs

 

Non respirable refers to 10-100 microns; which includes thoracic, and inhalable (inspirable). thoracic dust particles are under 25 microns, and inhalable dust particles are under 100 microns in diameter.

 

Each type of dust exists in the air we breathe; the only difference between them is the diameter of the dust particle. The dust sampling method varies, depending upon the type of dust to be evaluated.

Air quality is a serious issue in an industrial setting where dust can affect our sinuses, lungs, and entire respiratory system with potentially very serious consequences. Understanding the differences in dust particles, the various types of filters available is essential to maintaining a safe and healthy working environment.

If you lined up 25,400 one micron particles in a row they would measure one inch in length.

 25,400 microns in an inch

Slide 11

Abbreviations may include:

Abbreviations for exposure limits

A manufacturer will list the exposure limit based on numbers provided by OSHA  andthe amount of the permissible exposure in that particular region.

Permissible Exposure Limit (PEL) is the maximum amount or concentration of a chemical that a worker may be exposed to under OSHA regulations.

Threshold Limit Value (TLV)  refer to airborne concentrations of chemical substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed, day after day, over a working lifetime, without adverse health effects.

Threshold Limit Value—Time–Weighted Average (TLV–TWA). The TWA concentration for a conventional 8-hour workday and a 40-hour workweek, to which it is believed that nearly all workers may be repeatedly exposed, day after day, for a working lifetime without adverse effect.

Threshold Limit Value—Short-Term Exposure Limit (TLV–STEL). A 15-minute TWA exposure that should not be exceeded at any time during a workday.

Threshold Limit Value—Ceiling (TLV–C). The concentration that should not be exceeded during any part of the working exposure.

Slide 12

• Not all chemicals are tested
• You can still sustain damage from a chemical even with the rating.
• Higher TLV number safer the product
• Lower the TLV number less safe the product

 Slide 13

Particulate Respirators:

Particulate respirators are the simplest, least expensive, and least protective of the respirator types available. These respirators only protect against particles (e.g., dust). They do not protect against chemicals, gases, or vapors, and are intended only for low hazard levels. The commonly known “N-95” filtering face piece respirator or “dust mask” .

  

 

 

Slide 14 Respirators

Respirators are used to protect workers from occupational diseases caused by breathing air contaminated with harmful atmospheric contamination. A respirator shall be provided by the employer for each employee when such equipment is necessary to protect the health of the worker. The employer will provide the respirators that are applicable and suitable for the purpose intended. The employer is responsible for the establishment and maintenance of a respiratory protection program in the work place.

 https://www.osha.gov/SLTC/etools/respiratory/index.html

 

Slide 15

All respirators that rely on a mask-to-face seal need to be annually checked to determine whether the mask provides an acceptable fit to a wearer. The qualitative fit test procedures rely on a subjective sensation (taste, irritation, smell).  The quantitative test uses measuring instruments to measure face seal leakage.

The workplace exposure level determines what constitutes an acceptable fit and which fit test procedure is required. For negative pressure air purifying respirators, users may rely on either a qualitative or a quantitative fit test procedure for exposure levels less than 10 times the occupational exposure limit. Exposure levels greater than 10 times the occupational exposure limit must utilize a quantitative fit test procedure for these respirators.

 

Slide 16

Chemical Cartridge/Gas Mask Respirator: Gas masks are also known as “air-purifying respirators” because they filter or clean chemical  gases out of the air as you breathe. This respirator includes a facepiece or mask, and a cartridge or canister. Straps secure the face piece

to the head. The cartridge may also have a filter to remove particles.  Gas masks are effective only if used with the correct cartridge or filter for the chemical substance. Selecting the proper filter can be a complicated process. There are cartridges available that protect against more than one hazard, but there is no “all-in one” cartridge.  It is important to know what hazards you will face in order to be certain you are choosing the right filters/cartridges.

 Chemical Cartridge/Gas Mask respirator:

• Uses replaceable chemical cartridges or canisters to remove the contaminant.
• Are color-coded to help you select the right one.
• May require more than one cartridge to protect against multiple hazards.

 

Powered Air-Purifying Respirator (PAPR):

Powered air-purifying respirators use a fan to draw air through the filter to the user. They are easier to breathe through; however, they need a fully charged battery to work properly. They use the same type of filters/cartridges as other air-purifying respirators. It is important to know what the hazard is, and how much of it is in the air, in order to select the proper filters/cartridges.

 

Self-Contained Breathing Apparatus (SCBA):

is the respirator commonly used by firefighters. These use their own air tank to supply clean air, so you don’t need to worry about filters. They also protect against higher concentrations of dangerous chemicals. However, they are very heavy (30 pounds or more), and require very special training on how to use and to maintain them. Also, the air tanks typically last an hour or less depending upon their rating and your breathing rate (how hard you are breathing).

 

Slide 17

How are particulate filters classified?

There are nine classes of particulate filters which are broken down into three series: N, R, and P. The N series filter is used in environments free of oil mists. The R series filters can be exposed to oil mists, but should only be worn for one work shift. The P filter can be exposed to oil mists for longer than one work shift.

Slide 18

Also in this module are videos about air-purifying and face filtering respirators. Watching the video does not make you an expert in using the air-purifying respirators. If you are planning on using a chemical that requires the use of a air-purifying respirators be sure to participate in  your employer fitting, testing and maintenance  training programs in your work place.

Bibliography

https://www.osha.gov/dsg/topics/silicacrystalline/

https://www.osha.gov/silica/

http://www.ucc.ie/academic/chem/dolchem/html/comp/co2.html

https://www.jlab.org/ehs/ehsmanual/6681.htm

https://www.thoracic.org/professionals/clinical-resources/environmental-and-occupational/clinical-cases/pages/case2.php

[1] https://www.osha.gov/dsg/topics/silicacrystalline/

[2] https://aflcio.org/press/releases/afl-cio-applauds-new-lifesaving-silica-dust-rules

[3] https://www.osha.gov/silica/

[5] https://www.jlab.org/ehs/ehsmanual/6681.htm