FIT TEST METHODS

 

Qualitative fit test methods

General Precautions

The wearer should not eat, drink (except plain water), smoke, or chew gum for at least 15 minutes before the test.

 

Before carrying out a qualitative fit test using a distinctive taste or smell, the taste or smell threshold of the wearer must be established. This is often referred to as a ‘sensitivity test’. This screening test is carried out to check that the wearer can detect the taste of the test aerosol or detect the banana like smell employed in the odour test. If the wearer cannot detect the taste or smell during the screening test then the fit test method cannot be used and a different method should be chosen. The fit test should be carried out in accordance with the manufacturer’s instructions.

 

Ensure that the sensitivity solution is used during the threshold screening test

and that the more concentrated test solution is used during the actual fit test.

 

The nebuliser may clog during use and stop delivering the test aerosol, the test

operator should make periodic checks of the nebuliser to ensure that it is not clogged. If clogging is found at the end of the test session, the test is invalid. Regularly cleaning of the nebuliser should help to prevent clogging.

 

Test procedure

The fit test procedure should be carried out in accordance with the manufacturer’s documented instructions but following the test exercises given at the end of this document.

 

Bitter/sweet tasting aerosol fit test method

The person is fit tested while wearing the respirator inside a hood as shown while the test solution (either bitter or sweet) is sprayed into the hood. If the wearer detects the taste of the aerosol during the test then the fit is unsatisfactory and the fit test is failed. During this test, the wearer will carry out a number of specified exercises. If the wearer passes the fit test a fit factor of 100 is assumed (minimum). It is less costly when compared to quantitative fit testing methods.

 

Types of respirators that can be fit tested with this method include:

1. Filtering facepieces FFP1, FFP2, FFP3

2. Half facemask respirators fitted with a particulate or combined filter.

Qualitative fit test - taste

Odour fit test method (isoamyl acetate)

The person is fit tested while wearing the respirator inside an enclosure, which

contains a known concentration of isoamyl acetate (also known as banana oil). If the

wearer detects the smell of the isoamyl acetate during the test then the fit is

unsatisfactory and the fit test is failed. During this test the wearer will carry out a number of specified exercises. If the wearer passes the fit test a fit factor of 100 is assumed (minimum).

 

Types of respirators that can be fit tested with this method include:

1. Half mask respirators fitted with a type an organic vapour filter.

 

FIT TEST EXERCISES

For quantitative and qualitative methods, the test protocol should comprise

of a minimum of 7 exercises; each test exercise should be performed for at least one minute. During the quantitative fit tests, the exercises should allow for an in-facepiece sample period of at least 60 seconds. The exercises are:

 

Exercise Description

Normal breathing The wearer should breathe normally with no head movements or talking.

 

Deep breathing The wearer should breathe slowly and deeply, taking care so as not to hyperventilate.

 

Turning head side to side The wearer should slowly turn their head from side to side between the extreme positions on each side (approximately 15-20 times per minute). The head shall be held at each extreme momentarily so the wearer can inhale at each side.

 

Moving head up and down The wearer should slowly move their head up and

down (approximately 15-20 times per minute). The wearer should be instructed to inhale in the up position (i.e. when looking toward the ceiling).

 

Bending over The wearer should stand and bend at the waist as if to touch their toes.

 

Talking The wearer should talk out loud slowly and loud enough so as to be heard clearly by the fit tester. The wearer should read from a prepared text rainbow passage see below or count up to 100.

 

Normal breathing Same as exercise 1.

Rainbow Passage

“When the sunlight strikes raindrops in the air, they act like a prism and form a rainbow. The rainbow is a division of white light into many beautiful colours. These take the shape of a long round arch, with its path high above, and its two ends apparently beyond the horizon. There is, according to legend, a boiling pot of gold at one end. People look, but no one ever finds it. When a man looks for something beyond his reach, his friends say he is looking for the pot of gold at the end of the rainbow”.