We have all seen 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! However, on the other side of the argument, most written CS entry programs and training materials do NOT provide the knowledge needed by an entry supervisor to determine the proper size of the blower required 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.
Directions:
1) Determine the size (CFM) of the space to be ventilated
2) Obtain the blower capacity from the nameplate 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 diagonal one) is the amount of time that SPECIFIC BLOWER will need to VENTILATE that SPECIFIC SPACE properly.
NOTE: This tool is based on 7 Air Changes per Hour (ACH) and works ONLY in open spaces. Spaces with obstructions, such as baffles, must have EACH section ventilated.
