Knowing the distinction between single and double jacket fire hoses is essential to determining what is best for your project and application. If you are new to buying hoses, it may surprise you to learn that although there are attributes that set these hoses apart, their construction is quite similar.
Before you understand their differences, it’s important to understand their common construction, so let’s start there.
Single vs. Double Jacket: Cut from the Same Cloth
Single jacket hose and double jacket hose are made up of the same two components: The inner lining and the outer jacket(s). The inner lining in a modern fire hose is a single ply of EPDM rubber. The characteristics of EPDM rubber are its durability and resistance to chemicals. The rubber lining itself, although designed with a tensile strength of 1800 PSI, will not hold fluid pressure. Without a jacket, the tube itself would essentially blow up like a balloon and burst!
The linings are inserted and pulled through the jackets. They are then subjected to a steam vulcanizing process that bonds the jacket to the lining. The woven jacket consists of ring spun polyester yarns that are engineered to resist abrasion, mold, and mildew. The jackets are woven on large circular looms specific to the size of the fire hose they will ultimately become.
The jacket gives the hose its strength and pressure rating. While the majority of jacketed hose is white, there are a variety of colors available. To achieve coloration, the jacket is impregnated with a dye, also known as hypalon coating.
Differences Between Single and Double Jacket Hose
Simply put, the difference between single jacket and double jacket fire hoses is the number of polyester jackets. The double jacket hose has an extra layer (“jacket”) of woven fabric that boasts a higher wearability in comparison to the single jacket hose. It has an impressive burst test of 1,200 PSI and a 400 PSI service test.
In comparison, a single jacket fire hose is burst tested to 900 PSI. In order to meet NFPA requirements, single jacket hose must be service tested annually to 300 PSI.
Pros and Cons of Double and Single Jacket Hose
Although the double jacket hose is more costly than the single jacket, the extra layer helps protect it from burns, wear, and other damage. As a result, it posses a service life that is double that of its single jacket counterpart, living up to its name in more than one way!
However, if you aren’t using the hose for a heavy-duty application or if the need is temporary, you may choose the more economical single jacket hose. It’s also a little lighter, which is important in situations when the hose must be carried. For that reason, single jacket hoses are often used in forestry and for wildland fires.
Types of Single and Double Jacket Hoses
Did you know that there are many types of single jacket hoses as well as double jacket? Each type has it’s own construction and unique application.
1. Rack and Reel
A Rack and Reel fire hose is technically a single jacket hose manufactured to meet a specific application. Hospitals, airports, hotels, and other municipal or public buildings typically have these hoses pre-folded in a pin rack or cabinet for fire emergencies.
MSHA (Mine Safety and Health Administration) approved hose is also another type of single-jacketed hose. MSHA hose meets certain specifications and has the ability to self-extinguish when a flame source is removed. The lining of a MSHA hose is made of synthetic rubber, which does not produce toxic gases when ignited.
3. Mill Discharge
Last but not least is the mill discharge, sometimes dubbed the contractor hose. The mill discharge hose comes both single jacketed and double jacketed.
Though similarly constructed to regular single and double jacket hoses, these variations have a slightly lower pressure rating. Often times, construction sites, parks, or agriculturists will employ these hoses for undemanding purposes such as watering crops, draining a pond, or simply transferring water from A to B. It is important to note that for washdown purposes, a rubber-covered hose is the way to go.
When it comes down to it, choosing the correct hose for your application is crucial, both for your safety and for your project’s timely completion.