from the fravalet™ company limited

From The FRAVALET™ Company Limited

Innovation in Health Care Delivery

Professor R. P. Clark & M. L. de Calcina-Goff The FRAVALET Company Limited

KI-DISCUS

Presented by

Professor Raymond Clark OBE

CEng FSEE and

Professor M. Leonardo de Calcina-Goff FSEE FBPA

A summary of the basic steps to be taken in performing a KI-DISCUS containment test


KI-DISCUSContainment Testing System

KI-DISCUS is manufactured by:

Containment Technology Limited9 Telford Road

Ferndown Industrial Estate

Wimborne

Dorset

BH21 7QW

United Kingdom

Managing Director David Pollington

Telephone: + 44 (0) 1202 870189

Fax: + 44 (0) 1202 870212


To provide worker and environmental protection the air flows at the front apertures of open fronted containment facilities must adequately contain potentially pathogenic aerosols that may be generated in the working area.

This is a requirement of Standards and Regulatory Authorities

BIOLOGICAL SAFETY - relies very much on good safety cabinets and other LEV systems

The FRAVALET Company LimitedProfessor R. P. Clark & M. L. de Calcina-Goff

Flow visualisation and air velocity measurements complement safety cabinet performance assessment but cannot take the place of containment tests

The sequence of performance tests for the front aperture is:

1. Flow visualisation

2. Air velocity measurement

3. Containment to measure OPERATOR PROTECTION FACTOR

1

2

3


In the 1970’s Schlieren cine-photography dramatically identified poor performing cabinets where potentially contaminated air would spill out of the cabinet and surround the worker

These studies highlighted the need for tests to measure containment or “OPERATOR PROTECTION”

Schlieren flow visualisation puts containment on the map


Development of containment tests

Originally a microbiological test was used with spores or bacteria sprayed towards the front aperture

However, this produced contamination and could be dangerous

Another easy and safe test was needed and KI-DISCUS was developed


How to carry out KI-DISCUS containment tests


The directions given here apply equally to Class I and II safety cabinets as well as fumecupboards, open fronted cabinets for radiopharmaceutical and cytotoxic work etc.


First make sure that the cabinet or cupboard to be tested has been properly decontaminated according to regulatory authority requirements (COSHH in the UK)


Wheel the KI-DISCUS equipment to the front of the cabinet to be tested and disassemble the various parts of the trolley


It is important to find a clean, dry bench top away from the cabinet for the filter development equipment

Lay out the two small glass dishes, one filled with palladium chloride and the other with distilled water, together with the filter papers (to dry the membranes from the samplers), the magnifier and 3 pairs of tweezers


Return to the cabinet and begin to assemble the components at the front aperture

The trolley is placed at the centre line of the aperture. The artificial arm is assembled and placed in the circular support in the air suction tube mounted in the base of the KI-DISCUS trolley


The suction tube is next adjusted in height so that the artificial arm is level

The spirit level built into the end section of the arm indicates when it is level


The air samplers are next positioned at the aperture

Two air samplers are placed on the spigots on either side of the arm. The support for holding the upper two samplers is assembled and the samplers placed in the prescribed positions. The air hoses are connected to the suction take off points in the lower part of the trolley.

The air samplers are placed between 150-160mm from the plane of the aperture. The openings of the upper 2 are placed level with the top of the aperture


>250

150-160

100

65-75

155155

150150

CL

KI-Discus arrangement - Class I cabinet

The FRAVALET Company Limited

Professor R. P. Clark & M. L. de Calcina-Goff


KI-Discus arrangement - Class II cabinet

>250

150-160100

65-75

155155

150150

CL


The spinning disc generator is next positioned according to the type of cabinet being tested

For a Class I cabinet or fume cupboard the generator disc is placed centrally under the arm with the disc edge 100mm inside the cabinet as measured from the plane of the aperture

For a Class II safety cabinet the spinning disc is placed level with the top of the aperture and again 100mm inside the cabinet


The air samplers are next loaded with the filter membranes

The filter loading may be done either with the samplers in position in front of the aperture or with them taken to a bench away from the cabinet

To avoid contamination it is most important that one pair of tweezers is dedicated to loading the membranes into the air samplers. Care must be taken to ensure that the blue “separator” discs between the white membranes are removed before the membranes are placed in the samplers


The air flow through the samplers is next adjusted

Once the samplers are loaded and placed on their suction tubes, the air flow through them is adjusted using the barrel valve on each sampler. The suction pump is switched on and the pressure gauge is attached to the measuring point on each sampler in turn

The barrel valve is adjusted to give a reading of 8 ins wg (200mm wg) which ensures the correct air flow rate through the sampler orifice of 100 litres/minute


Setting up the spinning disc generator

The time for the peristaltic pump to deliver 20ml will previously have been measured and the run time set on the digital timer.This ensures that when the start button is pressed exactly 20 ml of KI will be dispensed on to the spinning disc for aerosolization

To prime the tubing to the spinning disc, on MANUAL CYCLE, switch on the pump until KI has completely filled the supply line to the spinning disc.

Once everything is set up, the test begins by pressing the automatic start button


Developing the filter membranes after the test

At the end of a test the spinning disc and air samplers will automatically stop in the correct sequence.

Remove the filter membranes from the samplers using the sharp pointed tweezers (designated solely for this purpose)

Without wetting the tweezers place the filter into the palladium iodide solution with the surface on which any KI landed, upwards


After some 20 seconds the development process will be complete

Use a third pair of tweezers (again designated solely for this purpose) to remove the filter membrane from the palladium chloride .

Rinse the filter membrane in water in the second glass dish and lay it to dry on the filter paper

When the filter membrane is fully impregnated with palladium chloride the chemical reaction turning KI into palladium iodide will be complete


The magnifier is used to identify and count the number (n) of grey/brown dots on each filter membrane

The protection factor (PF) is evaluated from the formula: PF = (62 x 105) ÷ n

If there are more than 62 spots on ANY ONE filter membrane then the test has failed and the protection factor is less than 105

The convention is that membranes from all sampling heads must EACH have fewer than 62 dots for the cabinet to pass the test


At the end of a series of tests the spinning disc and artificial arm must be carefully cleaned and dried using soft tissues and water

Careful cleaning will solve most contamination problems


It is also important to wipe the cabinet to avoid possible staining of painted surfaces


KI-DISCUS

The EndPresented by:

Professor Raymond P. Clark OBE CEng FSEE HonFRPS &

Professor M. Leonardo de Calcina-Goff ASIS FRPS FSEE FBPA


INNOVATION IN HEALTH CARE DELIVERY

5 B High Street, Newport Pagnell, Buckinghamshire, MK16 8AR

Telephone: 01908 211790 Email: [email protected]


from the fravalet™ company limited

Documents

calcinagoffthe directions

containment testsoriginally

calcinagoffflow visualisation

kidiscus equipment

good safety cabinets

open fronted cabinets

air flows

contaminated air