Glossary

ACGIH - American Conference of Governmental Industrial Hygienists (USA)

ACoP - Approved Code of Practice

Additive Effect
Substances are said to be additive in their effects when they act either on the same organs or by the same mechanism such that the effects reinforce each other.

Airfed Respirators
A continuous flow of clean air is supplied to the wearer via an airline.

AIHA - American Industrial Hygiene Association (USA)

APF - Assigned Protection Factor
As detailed in HSG53, the level of respiratory protection that can realistically be achieved in the workplace by 95% of adequately trained and supervised wearers.

AX
Filters for use with low boiling organic vapours (boiling points below 65° C).

BSi - British Standards Institute

CABA - Compressed Air Breathing Apparatus
A general description for CALA and SCBA .

CALA - Compressed Airline Apparatus
A positive pressure of clean air is supplied to the wearer via a compressed airline.

CE Mark
Symbol printed on the product/ packaging that informs the market that the product meets the essential requirements of the European directives relating to PPE. It could be described as a 'passport' to sell products within the European Union. It is not a quality mark.

Cool Flow valve
Proprietary 3M exhalation valve. A low breathing resistance valve that allows exhaled air to escape from a respirator.

COSHH - Control of Substances Hazardous to Health Regulations (United Kingdom)

Dusts
Created when solid materials are broken down into fine particles that float in the air before settling under gravity. Dusts are produced by operations such as grinding, drilling, blasting, sanding and milling .

EN - European Standard
Technical documents agreed by experts from European countries stating minimum performance requirements and testing methods for a given type of PPE.

EPDM
Rubber used in the manufacture of some facepieces.

Escape Sets
Small cylinders of compressed air are used to supply clean air to a hood or mask for escape situations.

Fullface mask
An RPE device which covers the eyes, nose, mouth and possibly the chin.

Fumes
Created when solid materials vaporise under high heat and then condense. For example metal vapour cools and condenses into extremely small particles, with a particle size generally less than one micron in diameter. Metal fumes can come from operations such as welding, smelting and pouring of molten metal.

Gases
Substances that are similar to air in their ability to diffuse or spread freely throughout a container or area. Examples include oxygen, carbon monoxide, carbon dioxide, nitrogen and helium.

Half Mask
An RPE device which covers the nose, mouth and possibly the chin.

HASAWA - Health and Safety at Work etc. Act 1974 (United Kingdom)

HSA - Health and Safety Authority(Ireland)

HSC - Health and Safety Commission(United Kingdom)

HSE - Health and Safety Executive(United Kingdom)

IDLH - Immediately Dangerous to Life or Health
This is the concentration considered Immediately Dangerous to Life or Health (IDLH) as defined by the NIOSH. The IDLH concentration is defined as "that poses a threat of exposure to airborne contaminants when that exposure is likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment."

The IDLH value represents a maximum concentration from which a worker would escape within 30 minutes without any escape impairing symptoms or any irreversible health effects.

I.S. - Intrinsically Safe
The measures applied in the construction of electrical apparatus to prevent ignition of the surrounding explosive atmosphere by the apparatus.

Mists
Tiny liquid droplets formed from liquid materials by atomisation and condensation processes. For example, mists can be created by:

• Spraying operations
• Plating operations
• Mixing and cleaning operations

MMDF - Manufacturers Minimum Design Flow
The minimum air flow rate that will provide adequate levels of protection for powered and supplied air equipment.

MSDS - Material Safety Data Sheet
A document published by the manufacturer/processor of a substance that includes information on its usage and handling. This may include toxicological effects, level of flammability and a breakdown of compounds. Manufacturers are obliged by law to provide a MSDS.

Negative Pressure Respirators
The wearer's lung power draws contaminated air through a filter. The respirator relies on a good face seal to prevent contaminants bypassing the filter material.

NIOSH - National Institute for Occupational Safety and Health (USA)

NPF - Nominal Protection Factor
The theoretical protection level of a respirator based on laboratory measured performance data.

Calculated by dividing 100 by the maximum allowed Total Inward Leakage value as specified in the relevant Standard. For example: EN149 class FFP3 has a maximum allowed total inward leakage of 2%. 100 divided by 2 equals 50. Therefore the NPF of an FFP3 respirator is 50.

Odour Threshold
The concentration of an airborne substance that can be detected by smell or taste.

OSHA - Occupational Safety and Health Administration (USA)

Oxygen Deficiency
Occurs when the percentage of oxygen in the air falls below 19.5% (3M definition). It can be caused by chemical reaction, fire or when other chemicals displace oxygen from the air.

PAPR - Powered Air-Purifying Respirator
A fan is used to draw contaminated air through a filter and provide the wearer with clean air. The respirator relies on a good face seal to prevent contaminants bypassing the filter material. Also known as Powered Air Respirators.

Particulates
Dusts, Fumes and Mists are often grouped together and described as Particulates.

Powered Air Respirators
A fan is used to draw contaminated air through a filter and provide the wearer with clean air. The respirator relies on a good face seal to prevent contaminants bypassing the filter material. Also known as PAPR.

PPE - Personal Protective Equipment

QLFT - Qualitative Fit Testing

QNFT - Quantitative Fit Testing

RPE - Respiratory Protective Equipment

SCBA - Self Contained Breathing Apparatus
Cylinders of compressed air are used to supply clean air to the wearer's facepiece.

Sen - Respiratory Sensitiser

Sk - Skin notation
Substance may pass through intact skin.

Smoke
Airborne mixture of gases and particles. Created by fire or other high-energy heat source.

STEL - Short Term Exposure Limit

Supplied Air Respirators
Are respirators where clean, breathable quality air is supplied from an independent source direct to the facepiece.

Synergistic Effect
Substances are said to be synergistic in their effects when they act either on the same organs or by the same mechanism such that the overall effect is considerably greater than the sum of the individual effects.

TH - Turbo Hood or Helmet

TIL - Total Inward Leakage

TLV - Threshold Limit Value
TLVs are personal exposure limits set by the ACGIH in the USA. There are two reference periods for which the TLVs may be set; 8 hour Time Weighted Average (TWA) and 15 minute Short Term Exposure Limit (STEL).

TM - Turbo Mask

TWA - Time Weighted Average
There are two reference periods for which the WELs may be set; 8 hour Time Weighted Average (TWA) and 15 minute Short Term Exposure Limit (STEL). A substance may be assigned WELs set at either one or both reference periods.

• 8 hour TWA - Some adverse health effects require prolonged or accumulated exposure. The 8 hour TWA is to set to control these effects by restricting the total intake by inhalation over one or more shifts.

• 15 minute STEL - Some adverse health effects may be seen after short exposures. 15 minute STEL may be applied to control these effects.

Type & Class
A symbol that denotes the type of device and the level of protection afforded. E.g. FFP2 - a filtering facepiece respirator for particulates with Class 2 level of performance.

Vapours
The gaseous state of substances that are either liquids or solids at room temperature. They are formed when solids or liquids evaporate. Petroleum is an example of a liquid that evaporates easily, producing petroleum vapour. Other examples are paint thinners and degreasing solvents.

WEL - Workplace Exposure Limit
Personal exposure limits set by the HSE. Each WEL guideline represents the workplace exposure levels to which it is believed nearly all individuals could be exposed repeatedly without experiencing adverse health effects.

WPF - Workplace Protection Factor
A level of respiratory protection measured in the workplace for equipment that has been properly selected, fit-tested, maintained and used correctly.

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