When dealing with roof coating it is important to know the volume of the spray foam and polyurea materials that are covering roof surface. Materials are packed, sold and shipped based on the their weight. Therefore, in order to find out the volume of a product packaged in the container, converting the weight of the product within the drum into gallons is required. To do so, the would need a specific gravity or weight per gallon of material information. There is likely to be a difference across manufacturers, so confirm with the product supplier to provide this info or if a scale is available, weigh the container first. Specific Gravity and per gallon weight of the liquid for some manufacturers are provided on the SDS or product data sheet (formerly MSDS).
When the weight of one gallon of product is known, divide the weight (in pounds) of one gallon of the product by 8.33 lbs. (the weight of one gallon of water). This will provide the specific gravity.
When the specific gravity is known, multiply the specific gravity by 8.33 (the weight of one gallon of water). This will provide the weight of one gallon of the product.
Utilize one of the two following equations to figure how much volume in gallons is in the container:
NET WEIGHT OF LIQUID / (SPECIFIC GRAVITY*8.33)=VOLUME (IN GALLONS)
NET WEIGHT OF LIQUID / WEIGHT PER GALLON=VOLUME (IN GALLONS)
Many manufacturers have made the necessary calculations and have adjusted the drums accordingly while others have not. So, a little due diligence on our part will provide the necessary info to determine how the products are packaged and aid when confirming stroke counter limits.