We have all seen it... a blower the size of a lunch box attempting to ventilate a 500,000 gallon vessel! The permit calls for a "blower" so to meet the permit conditions, the team grabs the nearest available blower and NOT necessarily the CORRECT BLOWER! But on the other side of the argument, most written CS Entry programs and training materials do NOT provide the knowledge for an entry supervisor to determine the proper size of the blower needed for their entry permit. This "straight-line" tool makes this SIMPLE, FAST, and EASY!!
To use the tool, all one needs is a straight edge, such as a ruler, pen, or even a piece of paper! All anyone needs to know is the SIZE of the space and the size of their blower and the tool will tell them how long it will take THAT SPECIFIC BLOWER to ventilate THAT SPECIFIC SPACE.
1) Determine the size (CFM) of the space to be ventilated
2) Obtain the blower capacity from the name plate on the blower
3) Using a straight edge, place one end on the vertical scale on the left (Confined Space Volume); place the other end of the straight edge on the Blower Capacity Column (right side)
4) Where the straight edge passes through the middle column (the slanted one) is the amount of time that SPECIFCI BLOWER will need to properly VENTILATE that SPECIFIC SPACE.
NOTE: this tool is based on 7 Air Changes per Hour (ACH) and works ONLY on open spaces. Spaces with obstructions such as baffles need to have EACH section ventilated.