HOW HOSE SPACE IS DETERMINED IN DESIGN OF FIRE APPARATUS
Four Leading Builders of Motor Fire Apparatus Give Design Factors for Hose Storage
How builders of fire apparatus determine the size of hose body to accommodate a specified load of hose is indicated by the table and comments herewith.
Four of the leading builders were contacted. and the information they have provided will prove of interest and use to those anticipating the purchase of fire apparatus.
Their statements are as follows:
Co. A.: We have made it a standard practice of figuring our hose body capacities on triple combination units by using a factor of 90 cubic inches per foot of 2 1/2-inch hose, and for city service jobs, with top mounted hose compartments, we have a minimum factor of 80 cubic inches per foot of 2 1/2-inch hose.
These factors have been time tested and are from experience, and we have taken into account the packing of brand new hose of all types and manufacture.
Co. B.: We have a practice of figuring 80 cubic inches of body space for each foot of 2 1/2-inch standard fire hose to be carried. Usually, it provides for ample space for carrying hose. Quite frequently the customer finds that he can carry an extra 100 or 200 feet in a body that we have calculated for a 1000 feet on the above basis. It all depends on the kind of hose, the way it is laid, the age of the hose, etc.
We believe it would be an excellent idea if a commonly accepted formula for figuring hose body space could be standardized throughout the industry and to include not only 2 1/2-inch hose but 1 1/2-mch and 3-inch as well.
The following are the figures on which we base our hose body estimates for various sizes of hose:
1 1/2-inch hose requires 32 cubic inches per foot of hose.
3-inch cotton double jacketed hose requires 110 cubic inches body space per foot of hose.
3 1/2-inch double jacketed fire hose requires 135 cubic inches body space per foot of hose.
Co. C.: We figure 80 cubic inches of bodv space are required for each foot of 2 1/2-inch double jacket hose. Forty cubic inches required for each foot of 1 1/2-inch double jacket hose.
We rate all of our hose bodies for capacity based on the above figures.
Our figure was based on new hose, which is in some cases rather stiff and unwieldy, and we have adopted our figures as a matter of protection.
At one time we used a lower figure and ran into some complaints that they could not get all the hose in the body that we told them could he loaded.
Hose made by different manufacturers varies in its pliability, particularly when new, and so the actual footage will vary according to the make of hose laid in the body and also the type of hose loading pattern that is followed.
Co. D.: We figure 80 cubic inches to one foot in length of 2 1/2-inch double jacket hose and 40 cubic inches per foot in length of 1 1/2-inch double jacket hose. This is about 5 cubic inches more than the Army uses to figure and seems to be a fair average for most departments.
It makes a lot of difference whether the body has interfering wheelhouscs or not, and how many folds there are to 1000 feet of hose.
When extra size booster tanks arc used and shorten the hose body, then the rule does not work even at 80 cubic inches on account of increased number of folds.
Another problem is the make of hose. Some brands pack much better than others. White hose packs better than the wax and gum, which is stiffer.
The accompanying table presents the figures supplied by builders in a form for easy comparison.