BS 8628 – Disinfection Using Ultraviolet Radiation

Ultraviolet (UV) irradiation has been known for decades as a terminal disinfection method, widely used in a variety of applications including healthcare, agriculture, water and food treatment, as well as in airlines and many other settings. Due to the rapid nature of the decontamination (normally between as little as 5 minutes to 45 minutes), UV devices have been implemented within healthcare settings as a quicker alternative or to complement fogging automated systems such as hydrogen peroxide dispersion technology.

UV disinfection has been shown to be a good complementation to the current manual cleaning practices, to help further reduce the risk of surface contamination. In terms of regulation, there has been a lack of standardised methodology to test UV devices in a comparable manner. For that reason, the European disinfectant standard writing body CEN has released a new standard that covers the requirements and methodology for testing the efficacy of UV devices: the BS 8628:2022.

This new standard has been based on the existing airborne surface disinfection standard EN 17272:2020 with some minor differences specific to UV devices. In brief, the UV device is placed within a blacked-out enclosed test chamber at a specified distance and location and switched on for a specified contact time. The process will be started remotely (no people present inside the chamber) and it will disinfect the surfaces and not the air in the room. Results are expressed in a logarithm scale to assess compliance with the standard.

What is the difference between the BS 8628 test and the EN 17272:2020 test?

The main difference the BS 8628 test and the EN 17272:2020 test is that the method only consists of one main phase, the Efficacy Test. The distribution test is not performed as UV devices are not intended to decontaminate the whole room but rather “close by” surfaces.

Efficacy Test of BS 8628:2022

How does the BS 8628 test work?

Stainless steel carriers are inoculated with a suspension of microorganism and interfering substance (replicating clean or dirty conditions) in triplicate per each organism and left to dry. Two control carriers are prepared similarly and will be left outside the test chamber with similar environmental conditions.

Once dry, they will be moved inside the chamber and placed horizontally over a flat black matt surface at a specified height with the inoculum facing up.

The UV system is then placed within the test chamber at specified distances from the challenge and the disinfection cycle is started.

The chamber must be equilibrated for temperature (as standard 20 ± 1 °C) and relative humidity (30-60%) before starting the cycle.

The total UV disinfection contact time is recorded, starting from the moment the UV lamps switch on to the point where they are switched off.

The carriers are then processed in a recovery liquid and plated out onto appropriate agar plates. The results are then counted, and the achieved efficacy is expressed in LOG reduction.

Our disinfectant product testing offering includes the BS 8628: Disinfection using ultraviolet radiation – Methods for quantitative testing of automated ultraviolet disinfection activities by direct illumination test standard.

Written by Enrico Allegra February 15th 2022

As a Clinical Microbiologist, Enrico has been working in the regulatory world of pre-clinical safety assessment for over a decade. He graduated with a Bachelor of Science degree in Immunology with medical Microbiology followed by a master’s degree in clinical microbiology Queen Mary University of London in 2013.

As part of his MSc’s project, he collaborated with the Barts Health NHS Trust to develop a diagnostic PCR cycle to detect Pneumocystis jirovecii in samples from immunocompromised patients. This helped reduce the turnaround time from several days to less than 12 hours.
During the height of the pandemic, he worked on the development of antiviral assays against Coronavirus as well as being part of clinical trial of bacteriophage technology to help fighting secondary infection of cystic fibrosis patients. Over the last few years, he has been actively involved the scientific community publishing various peer-reviewed papers for the introduction of novelty assays of safety assessments. He positively contributed pioneering new alternative to in vivo testing for cytotoxicity using insect models alongside cell culture testing. He is a certified biosafety officer acting as the Technical Lead at Test Labs for any UKAS ISO 17025 testing.

During his career he has worked as a Study Director conducting pre-clinical testing under GLP requirements working for a large CRO company. In this role he was able to gain expert knowledge for product testing to meet the requirements for regulatory submission to various authorising bodies, such as FDA, EPA, MHRA. He was heavily involved in method transfer and development, with a keen interest in bringing innovative testing procedures to meet client needs. As a result, Enrico used all his previous knowledge and expertise to help setting up the new Medical Device testing facility for Test Labs.

As part of his new role Enrico has helped the company achieving various new accreditations for Medical Device testing including the reprocessing validation for Class Ir Medical Devices under the scope of ISO 17025. Guiding the analytical team for reprocessing testing he has gained invaluable knowledge in customising testing regimes to accommodate reprocessing of reusable Medical Devices with emphasis on process optimisation and safety aspect.

Here at Test Labs, he acts as the Head of Laboratory overseeing the operation of Medical Device testing spanning from microbiology, chemistry and product testing. Guided by a deep understanding of product development and regulatory standards, he strives for excellence in both clinical evaluations and technical assessments.

BS 8628 – Disinfection Using Ultraviolet Radiation

What is the difference between the BS 8628 test and the EN 17272:2020 test?

Efficacy Test of BS 8628:2022

How does the BS 8628 test work?

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