Video – “How to Measure Captor Hood Control Distance?”
Latest OXYL8 LEV training video (Sept 17) on YouTube discusses the ways in which we can approach the verification of the Control Distance of a particular Captor Hood.
More usually we use smoke release on the centreline out from the hood face until the first ‘whisp’ of smoke is not controlled. From there most surveyors move back towards the hood 50mm and measure that distance. But ….. does that provide a true picture of the effectiveness of the hood. What if the hood is being used to control toxic fumes such as welding fume from stainless steel welding?
Fletchers Nomogram equations provide an accurate method of determining the Captor Velocity for a given hood at any selected distance out from the hood.
Should we be using Fletcher’s Equations to determine the Effective Range (ie Effective Control Distance) for Captor Hoods at Commissioning and/or Thorough Examination and Tests (TExTs)? The free design spreadsheet can be downloaded here:- Fletcher Excel Spreadsheet (see bottom of link page)
The video shows the issues, the potential pitfalls using smoke alone and discusses possible options.
Captor Hoods – How to Measure Captor Control Effectiveness (Captor Distances)