Journal contents list

< Issue 34 | Issue 35 | Issue 36 >

Issue 35: July/August 2018

Main features

Comparison of the removal of macroparticles and MCPs in cleanrooms by surface deposition and mechanical ventilation

W Whyte and K Agricola

Abstract →

Abstract

The removal of macroparticles (particles ≥5μm) and microbe-carrying particles (MCPs) from cleanroom air occurs by surface deposition or ventilation. In an operational ISO Class 8 cleanroom, small particles ≥0.3μm and ≥0.5μm are mostly removed by air (>99%). The size where half the particles are removed by deposition and half by mechanical ventilation is about ≥10μm, and 90% of particles are removed by deposition when the particle size is ≥40μm. Results were calculated for other ISO cleanroom classifications, and for particles ≥5μm the percentage deposited on surfaces varied from about 11% to 37%. The percentage of MCPs removed by surface deposition in Grade B, C and D cleanrooms that are graded according to the EU Guidelines to Good Manufacturing Practice (2005), varied from 8% to 26%.

← Close.

Getting rid of 95% UCL calculations in ISO 14644-1:2015 standard: new weaknesses and possible solutions

Alexander Fedotov

Abstract →

Abstract

Cleanroom testing and classification are considered by all parties involved in cleanrooms design, construction, testing and operation. There is a rather long history, but some unsolved problems still remained at the beginning of the 21st century. One of the problems was the unnecessarily complicated procedure of 95% UCL calculations using statistical tools. Field engineers were keen to abandon these calculations without losing any information. It is quite possible to do this by increasing the number of sampling points or setting lower concentrations for the class limits in the testing procedures. The new ISO 14644-1:2015 made a step forward and offered a much simpler method by allowing the use of single measurements or mean values simply by increasing the number of sampling locations. This paper discusses the pro and cons of this approach and offers alternative suggestions.

← Close.

Removal of airborne contamination using hydrogen peroxide vapour (HPV)

Shada Warreth, Michael Wood, and John Chewins

Abstract →

Abstract

Hydrogen peroxide vapour is an established method for removing microbiological contamination from surfaces. Whilst surface decontamination is well studied, the effect of vapour phase hydrogen peroxide on microbiological organisms within the air has not been well evaluated, with decontamination efficacy being generally assumed. Active viable monitoring of an ISO Class 7 / Grade B simulated cleanroom pre and post hydrogen peroxide vapour decontamination showed the elimination of all microbiological organisms from the air.

← Close.

Blog

VHP (Vapour Hydrogen Peroxide) fragility

Andrew Hopkins

Book Review

Review of 'Advances in Cleanroom Technology' by Bill Whyte

Gordon Farquharson

Life-lines

Conference report

Cleanroom Technology Conference 2018

Murielle Gonzalez

News

Connect 2 Cleanrooms wins Best Cleanroom Facility Award at Cleanroom Technology Conference 2018

Take-off for CRC's designs on space

Contec Rotational Disinfectants

Top marks for Cherwell's Redipor® prepared microbial media products

'Cleanzone Campus' - expanding cleanroom knowledge through research

China is home to twelve thousand cleanroom enterprises - by Cleanroom Guangzhou Exhibition Committee

Crowthorne Group extends research into the best methods to destroy contaminants for CL3 & CL4 facilities

Events and Training courses