ANSI Z9.5 Version 3 to be Published Fall 2012

The ANSI Z9.5 Laboratory Ventilation has been updated and the public review period has passed. It is anticipated that this third revision will be published in the fall of 2012. The first version was published in 1992 and the second version was published in 2003.
A quick highlight of the new requirements as it applies to Chemical Fume Hoods is as follows:
  • Where the design sash opening area is less than the maximum sash opening area, the hood shall be equipped with a mechanical sash stop.
  • Minimum Flow Rates: “… laboratory hoods shall maintain a minimum exhaust volume to ensure that contaminants are properly diluted and exhausted from a hood.” A list of factors to consider when setting the minimum flow rate is included.
  •  Ductless Fume Hoods – “A Hazard Evaluation and Analysis shall be conducted as directed in ANSI/AIHA Z9.7 and Section”
  • The acceptable face velocity range has been defined as 90 – 120% of benchmark velocity (as defined by ASHRAE 110 on site Testing). Any result outside of this range shall be corrected before further use.
  • The face velocity test method has been clearly defined.
  • ASHRAE 110 Pass / Fail has been clearly defined.
  • A procedure for measuring Cross Drafts is included.
LabTech Midwest has anticipated this publication for the past several years. The new document in draft form is a huge step forward in Laboratory Ventilation design, maintenance and testing. As with every new publication our test procedures will be updated with the new requirements as soon as this document is published.