Evaluation of the Operator Protection Factors Offered by Positive Pressure Air Suits against Airborne Microbiological Challenge

Abstract

Laboratories throughout the world that perform work with Risk Group 4 Pathogens generally adopt one of two approaches within BSL-4 environments: either the use of positive pressure air-fed suits or using Class III microbiological safety cabinets and isolators for animal work. Within the UK at present, all laboratories working with Risk Group 4 agents adopt the use of Class III microbiological safety cabinet lines and isolators. Operator protection factors for the use of microbiological safety cabinets and isolators are available however; there is limited published data on the operator protection factors afforded by the use of positive pressure suits. This study evaluated the operator protection factors provided by positive pressure air suits against a realistic airborne microbiological challenge. The suits were tested, both intact and with their integrity compromised, on an animated mannequin within a stainless steel exposure chamber. The suits gave operator protection in all tests with an intact suit and with a cut in the leg. When compromised by a cut in the glove, a very small ingress of the challenge was seen as far as the wrist. This is likely to be due to the low airflow in the gloves of the suit. In all cases no microbiological penetration of the respiratory tract was observed. These data provide evidence on which to base safety protocols for use of positive pressure suits within high containment laboratories.

Limiting factors for wearing personal protective equipment (PPE) in a health care environment evaluated in a randomised study

“…Consequently, there is a need to test various types of PPE for material compatibility, determination of protection factors, wearer comfort and additional adaptations to specific needs [2, 3]. So far, tests mimicking the event of a biological threat have been performed in different contexts, for example, the assessment of whole hospitals by the French “Biotox-Pirotox” Network [4], performance of resuscitation skills wearing PPE [5, 6], and evaluation of PPE protection factors [7, 8]. Furthermore, valuable experience was obtained from performing autopsies in BSL3 facilities of cases with severe acute respiratory syndrome coronavirus (SARS-CoV) in China [9].…”

Efficacy Testing of Personal Protective Filters on Biosafety Level 4 Positive Pressure Suits

“…2 There are two models for BSL-4 laboratories: a cabinet laboratory, where handling of pathogens is performed in a line of Class III biosafety cabinets, and a suit laboratory, where personnel wear positive pressure protective suits. 3 Cabinet laboratories can be ergonomically challenging for certain tasks and are not generally suitable for large animal work. 4 As a result, the majority of BSL-4 laboratories are suit laboratories, 5 where the workers enjoy enhanced range of motion and visibility compared with those working in cabinet laboratories.…”

Evaluation of Nine Positive Pressure Suits for Use in the Biosafety Level-4 Laboratory

“…The following year, a publication by Steward and Lever characterized operator protection factors of intact and damaged suits using a make and model not included in the previous study; however the use of an animated mannequin did not allow for consideration of user comfort. 6 With enhanced public scrutiny over recently publicized incidents involving high containment BSL-4 laboratories, there is a heightened sense of urgency to assure the public that these facilities operate in accordance with the highest levels of biosafety and biosecurity. Further, as new BSL-4 facilities are opening or in the planning phases, a clear need has been addressed to aid in the selection of program-specific positive pressure suits that are protective, user-friendly, and compatible with facility parameters, including backup air capacity and choice of disinfectant.…”

“…The following year, a publication by Steward and Lever characterized operator protection factors of intact and damaged suits using a make and model not included in the previous study; however the use of an animated mannequin did not allow for consideration of user comfort. 6…”