In order to understand the basics of Repiratory Protective Equipment it is important to clarify the following definitions 

DUST         Solid air-borne particles  e.g. Coal dust

MIST          Tiny liquid droplets suspended in the air   e.g. Spray 

FUME         Very fine temporary airborne particulates, usually created by heat e.g. Welding fumes

VAPOUR     A substance which has diffused/evaporated ito air   e.g. Petrol vapour

GAS            Air-borne at room temperature with no defined shape and expands freely  e.g. Oxygen

WEL            Workplace Exposure Limit set and approved by HSE and is the maximum allowable concentration of a substance

                    legally allowed in the Workplace. This is expressed as a Time Weighted Average (TWA) usually over 2 set periods

                    The list of substance WEL are published in the HSE EH40 document

STEL           Short Term Exposure Limit  -  maximum exposure permitted over a 15 min reference period

LTEL            Long Term Exposure Limit  -  maximum exposure permitted over an 8 hour reference period

IDLH            Immediately dangerous to Life or Health  -  level of concetration of a substance that is likely to cause death or

                    delayed/immediate adverse health effects or prevent escape from such an environment

NPF             Nominal Protection Factor   -  As APF but based on laboratory measurements for EN approval

APF             Assigned Protection Factor  -  Level of protection that a particular type of respirator can be expected to provide

                                                                     if fitted correctly - based on working measurements.

                                                                     e.g. An APF of 10 should reduce the exposure of airborne contaminants by x10

FFP             Filtering Face Piece

HM               Half Mask  -  A mask that covers the nose and mouth

FFM             Full Face Mask - A mask that covers the eyes, nose and mouth

FF                Face Fit  -  There is a requirement that masks are tested and assesed for closeness of fit in the workplace

                                       For Half Masks a simple Qualatative Test involving wearing a hood and introducing controlled

                                       bitter/sweet tasting solution to asses fit. For other Masks a quantatative test is required.

EH40            List of  WELs published By HSE 2011  for use to comply with COSHH regulations


Identify the Hazard - Dust, Metal fume, Gas, Vapour etc.

Asses the Hazard - Level, Toxicity, Exposure time, Other PPE protection

Select the proper Respirator - FFP, HM,FFM etc

Training in fitting & Use - to optimise Respiratory Protection                 


Medical facemasks are regulated by the Medical Devices Directive and are tested to and comply with

EN14683: Protection against Bacterial Contamination.

Defines the Bacterial Filtration Efficiency of the facemasks and divides its tests into 3 categories:

Part 1: Bacterial Filtration Efficiency in vitro (BFE) Standards of the filtration of a controlled concentration of Staphylococcus aureas.

Results: BFE of 95% = Type I BFE of 98% = Type II

Part 2: Breathing Resistance (Delta P) Testing of the air flow pressure passing through the mask.

Results: Type I & II (non splash resistant) = ​<5.0 mmH2O/cm2

Part 3: Splash Resistance Testing of a determined quantity of artificial blood sprayed on the mask.

Results: Type I & II not applicable Type IR & IIR minimum 120 mmHg

Medical masks are not PPE, they protect the patient and the surgical area from contamination.Medical masks prevent droplets being expelled into the environment by the wearer and protect patients in surgery from these being transferred to the operative site 


Current Standard EN149:2001+A1:2009

There are 3 main categories of masks

                                  FFP1                                                       FFP2                                                   FFP3

                  80% of particles < 2 microns                94% of particles < 0.5 microns          99.9% of particles < 0.5 microns

APF                              4                                                             10                                                        20

USE        Non toxic Dusts,Mists & Fumes           Harmfull Dusts, Fumes & Aerrosols       Toxic Dusts, Fumes & Aerosols

            e.g.Hand sanding, Drilling & Cutting         e.g. Glass Fibre, Metal & Plastics           e.g. Toxic Metals, Hardwood

                           Building Sector                                         Softwood Work                            Grain Dust, Mould spores

D          Indicates a mask has undergone additional Dolomite Clogging Test - easier breathing resistance for longer 

NR       Indicates Non-reusable  -  is approved for one shift use only

R          Indicates a mask can be used more than once, but must be cleaned and stored correctly between use

All masks are approved for Oil and Water aerosols 

Respirators are available with/without an exhalation valve

Advantages of a Valve include  -  Easier to exhale, cooler to wear, stays comfortable for longer and reduces eyewear misting

Disadvantages include  -  More expensive and the User can contaminate the immediate atmosphere 

Activated Carbon can also be incorporated into this style of mask which can offer protection against nuisance level smells and odours (below the WEL). 

FFP must not be used in atmosheres defficient in Oxygen (<19.5%)  or where gases and/or vapours are present

The presence of facial hair in the region of the faceseal will significantly reduce the protection provided.  

A note of caution  -  Nuisance Dust Masks although resembling a FFP are not Protective Devices and should not be used


EN140  -  is the European standard that covers the technical specifications for both Half & Quarter masks.

                Half mask (HM) is defined as covering the nose, mouth and chin 

EN136  -  is the European standard that covers the technical specifications for Full Face Masks.

                 Full Face mask  (FFM) is defined as covering the eyes, nose, mouth and chin. 


STANDARD    HAZARD  TYPE     CODE    COLOUR CODE    DESCRIPTION                                               APF HM      APF FFM            

   EN141              Gas/Vapour              A              BROWN          Organic Vapours with bp greater than 65C         10                 20

                                                                                                     Must have good warning properties

                                                             B                GREY           Inorganic Gases & Vapours                                 10                 20

                                                                                                     Not Carbon Monoxide

                                                             E              YELLOW         Acid Gases & Vapours                                        10                 20

                                                                                                      e.g. Sulpher Dioxide

                                                             K               GREEN          Ammonia                                                             10                 20

                                                                                                     including Ammonia derivatives

                                                             HgP3      RED/WHITE     Mercury Vapour                                                   10                 20

                                                                                                      includes Mercury compounds

                                                             NOxP3   BLUE/WHITE    Oxides of Nitrogen                                              10                 20

                                                                                                      single use only

    EN371                                                AX            BROWN        Organic vapours with bp less than 65C              10                 20

                                                                                                      single shift use only

    EN143              Particulates               P1             WHITE          Low efficiency                                                      4                   X

                                                               P2             WHITE          Medium efficiency                                               10                 10

                                                               PR            WHITE          High efficiency                                                     20                 40

    EN141 also classifies filters by capacity, with classes 1 - 3 being low, medium and high capacity, respectively

WARNING  DO NOT USE any Filtering Respirator if:

◗ In oxygen deficient atmospheres i.e. less than 19.5% by volume at sea level

◗ In poorly ventilated areas or in confined spaces

◗ In atmospheres where the concentration of toxic contaminants is unknown or is Immediately Dangerous to Life or Health (IDLH)

◗ where Gas or Vapour contaminants with poor warning properties i.e. odour, taste or irritation

◗ At concentrations of substance greater than those for which the respirator is marked or permitted by COSHH or other applicable


◗ Where chemicals are likely to ‘desorb’. In such cases, filters must only be used once then immediately discarded e.g. AX filters

Filtering Respirators - Maintenance

The COSHH regulations require that all ‘filtering’ respirators be thoroughly examined at least once a month (specifically 28 days), if in regular use. For filtering respirators used only occasionally, for short periods, against dusts or fumes of relatively low toxicity, longer intervals between examinations may be suitable, but must not exceed 3 months. The result of these examinations must then be noted on the Maintenance Record Card for the individual’s mask. These records should be kept for a period of five years.

There are specific masks with integral filters tested to EN405 which are approved for use for up to 30 days and then discarded       No inspection or record keeping is applicable in this case