8
STEP 8
After 60 to 72 hours, remove the dome with a razor. Retrieve the dish with the
calcium chloride and immediately place the lid back on and reseal using saved
vinyl tape. Re-weigh the container on the same gram scale used at the start of
the test. Record weight, date and time (W2) (T2).
Note the weight as nal weight (W2). Do not spill any of the calcium chloride
crystals from the container. If any crystals are spilled, the test must be rerun with
a new test kit.
CALCULATIONS
1. Determine the Exposure Time in hours.
Exposure time in hours: T = T2 - T1
(Time = End Time - Start Time)
2. Determine the weight gain of calcium chloride.
Weight gain in grams; ∆W = W2-W1
(Weight Change = End Weight - Start Weight)
Moisture Vapor Emission Rate (pounds/1000 sq. ft/24 hours)
Moisture Vapor Emission Rate = 120 x ∆W
T
Alpha Professional Tools
®
also provides on-line calculator at www.alpha-tools.
com/mcalc.aspx.
