Protect Your Lungs!

Knowing the Contaminants

In order to know a contaminant well, you have to be aware of four aspects

• Its name and physical state;
• Its toxic effects;
• Its characteristics for sensory detection;
• Its characteristic for cutaneous absorption and of eye irritation.

Know Your Respirator

It is crucial to know the functioning, restrictions and functions of the respirator you use.

In order to protect yourself from exposure to particles, it is usually enough to pass the contaminated air through a cloth screen or polyester foam that would block them. They all carry the approval number TC-21C. Some of them are generic and may be used for protection against many particle contaminants. Others are more specific and are to be used only in the case of very specific contaminants silica, blasting-related dust, asbestos, radon, mist, smoke, etc. Some of them are efficient in any kind of environment, while the efficiency of others is substantially decreased in the presence of oils that wet the filtering tissue and remove its static electricity.

It is not as easy to invent a filter capable of filtering gaseous contaminants. As a rule, the air is passed through clay grains, silica gel, activated charcoal or special plastics capable of absorbing the contaminants. These grains are kept in a cartridge or filter cartridge.

Cartridge respirators carry the approval number TC-23C and the gas masks have the number TC-14G. Within this group, there are generic cartridges capable of absorbing various kinds of gases and a series of specific cartridges for chlorine, paint, pesticides, sulphur dioxide, ammonia, carbon monoxide, etc.

Some gases are practically non-toxic, but they can replace the air, to the point that the oxygen level drops causing suffocation. If the oxygen percentage falls below 19.5%, it is considered to be dangerously low and you have to breathe air delivered by a pump or from bottles. These are supplied air respirators (TC-19C) and independent respirators (TC-13F).

Know the Environment Risk Level

Some types of environments are extremely dangerous. They pose an immediate risk to life and can have harmful and irreversible health effects. They may also incapacitate you when you try to leave the contaminated area. They are listed below:

• Atmosphere containing a known contaminant at a concentration close to the IDLH (immediate danger to life and health) level. A list of substances that are IDLH is published in the Pocket Guide to Chemical Hazards of the US National Institute for Occupational Safety and Health (NIOSH).
• Atmosphere containing a contaminant that is known and very toxic at an undetermined concentration. Carcinogens and substances that deposit themselves in the lungs without breaking down, such as silica or asbestos, are considered as particularly toxic.
• Atmosphere containing an unknown contaminant.
• Atmosphere where the oxygen level is below 19.5%.
• Atmosphere of a close contaminated space.
• Atmosphere containing contaminants at a concentration equal to or exceeding LEL (lower explosive limit). The book Dangerous Properties of Industrial Material by Sax, which is available in specialized libraries, lists the LELs.
• Atmosphere filled with fire smoke.

In order to enter these types of atmospheres, you must wear an independent respirator equipped with an air bottle.

Note: To be able to wear an independent respirator, you have to take a special course. You have to participate in the course at least once a year and it must include instruction and hands-on activities covering the issues of respiration control, as well as instruction in simulated use.

In order to know the risk posed by a given kind of atmosphere, its risk factor (RF) is calculated by dividing the contaminant's concentration in the air by its occupational exposure limit (OEL). By definition, the occupational exposure limit is the contaminant level to which you can be exposed continually, day after day during your whole working life without experiencing any negative health effects as a result. For companies under federal jurisdiction, the OEL is called TLV or Threshold Limit Value and is determined by the American Conference of Governmental Industrial Hygienists.

Note: RF = concentration in the air ÷ OEL

RF indicates by how many times the OEL is exceeded. Clearly, the higher this number, the more dangerous the atmosphere is. If there are many contaminants in the air, you have to calculate as many RFs as there are substances.

Note: Never enter a contaminated atmosphere if you do not know its risk factor.

Respirator Approval

Wear only the approved respiratory protection devices. For companies under federal jurisdiction, only the respirators approved by the NIOSH and listed in the Certified Equipment List are authorized.

Note: During the approbation procedure, the NIOSH determines a typical protection factor (TPF) for each respirator. The TPF of a given respirator must always be higher than the highest risk factor (RF) of all the contaminants present.

Face Adjustment

It is important that the respirator's mask be well adjusted to your face. Very often, men are required to be clean-shaven before using the device. Learn how to adjust the mask on your face and how to remove it and check the adjustments and seals before putting the mask on. Once you have the mask on, check the seals using the method established by your employer. Often, the chosen verification method would involve irritating smoke or a strong-smelling vapour, or under-or over-pressure tests.

Note: A respirator that is not well-adjusted to your face diminishes the TPF. You won't know any more if you are well protected or not.

Replacement

All particulate filters have a limited lifetime. Once the filter is clogged or you have hard time breathing, you have to replace it. There are disposable filters for short-time tasks.

All cartridges and filter cartridges have a limited lifetime. Once all grains are saturated, they no longer block gas contaminants, which pass right through them. There are three ways of determining when you can no longer use your cartridge or filter cartridge.

First method Some respirators (especially filter cartridges) are equipped with a small window, which changes colour once the grains become saturated. Once the color changes, replace your filter cartridge.

Second method Your employer can establish a replacement schedule based on concentration of contaminants in the air during your work time in this contaminated atmosphere. Once the established time of usage elapses, replace your cartridge of filter cartridge.

Third method Some substances have typical characteristics for sensory detection at concentrations equal to or lower than their OEL. Once you smell or taste the contaminant or as soon as you start feeling a certain irritation, replace your cartridge or filter cartridge.

Note: Never use a cartridge or box respirator if you do not know when it needs to be replaced.

Emergency and Rescue

Know what to do in case your respirator becomes defective, or when a power failure, an uncontrollable chemical reaction, fire, explosion or a human error occurs.

You have to know how to leave the contaminated area and the amount of time that it will take you. If needed, equip yourself with an emergency mouth respirator or a rescue air tank.

Many disasters happen during rescue operations. Stress levels are at their maximum, people are panicking and orders flow in from everywhere. Know what to do. Make sure you have plenty of emergency devices close to you.

Cleaning, Inspection, Maintenance and Storage

A respirator may be compared to an additional lung. You would never leave your lung on a shelf, exposed to free air, sun, cold, oil, mouse droppings, etc. The same applies to your respirator.

• Store your respirator in a clean place, in a hermetically closed bag.
• Wash it regularly and disinfect when needed.
• Check the replacement schedule.
• Make sure that the regulators, warning devices and alarm systems are in good working condition.
• Check your air tanks, if necessary.
• Check if all parts are present and are in good state. Otherwise, replace them.

Caution: The NIOSH approval is valid only for a complete respirator unit, which includes the straps, valves, face pieces, cartridges, boxes or filters, and air duct lines, if applicable. If you replace one of the above-listed pieces, parts or cartilages by one from another respirator from another type, the unit is no longer approved. For example, you cannot use a brand X cartridge for a Y brand respirator even if you can screw them on together. For each type of respirator, the manufacturer provides a list of pieces, parts and cartilages approved by the NIOSH and which can be joined together. Consult the list in order to be sure that you are protected.

Note: Wearing a respirator that does not protect you from the contaminants you are exposed to or does not protect you sufficiently can be very dangerous for your life, health and security.