And Im sure we all know, Air pressure drops as it moves through a hose. The longer the hose, the greater the pressure drop. That may have issues with the air tool running properly, yet, insufficient air reaching the air tool through a long hose can harm it.
Pressure drop is a concern for your air driven equipment. It might be worth your time to have a review of how pressure drop affects your air tool use.
Better to ramp up the pressure and enlarge the air hose diameter and length to run the air tool effectively than to run a too long extension cord to the portable compressor and possibly burn out the compressor motor.
Choosing a hose that works well is not a trivial matter. Be sure your hoses are CE certified, meaning they conform to all EU safety standards. The aim when choosing an air hose length is to strike a balance between maximum maneuverability with your air tool and a minimum loss of pressure. Here are some common defects that mean you’ll need a new hose rather than a repair:
– The connector or fixing is damaged
– The hose is bent, kinked or twisted beyond a point in which it’s usable
– A cut or abrasion is causing air leakage
– Too cold or dry air has caused premature wearing
– The pressure in your system is too high and has caused a seepage
Every air hose has a service life or duty cycle. Every hose will eventually wear to a point in which it becomes unusable depending on things such as the quality of the product, the frequency or use, and the material the hose is made from
With numerous varieties of air hose available to buy, sifting through all the choices and information can seem daunting. In reality, these really only four things you need to decide before you start your shopping:
- How long a hose do you need?
- What should the internal diameter of the hose be?
- What material should your hose be made from?
- Do you want a standard or recoil hose?
There are three main issues to consider when shopping for a hose:
· Length: The obvious one on the list; the hose needs to be as long as you need it to be.
· Sizing: The inner diameter of the hose will determine the maximum amount of air it can carry.
· Material: The material the hose is made from determines how flexible the hose is, and how long it will last.
Hoses come in different types to improve usability. There is no hose types that performs best in all applications. A 100ft hose will reach everything you’d ever want to reach, but it would also be much heavier and bulkier than it needs to be most of the time. Short, lighter hoses may be a better option for smaller jobs. At some point it becomes easier to move the compressor than it is to move the hose.
If you have the room, the pair of a short hose for shop work and a long extension hose for occasional jobs is a good loadout for your toolbox.
The inner diameter and maximum pressure rating of a hose determine its capacity to deliver air. Larger diameter hoses operating at higher pressure deliver more air. Most handheld tools such as nail guns and sprayers can be adequately supplies through a 1/4″ hose. 3/8″ diameter hoses are only necessary on runs longer than 100ft or when a large air tool is in use. When you are trying to figure out what hose size you need, or even why a 3/4″ hose is well over an inch in diameter, just remember the acronym H.I.D..
The ‘H’ in H.I.D. stands for HOSE. The ‘I.D.” in HID stands for the hose “inner diameter”.
Hose size is measured by its inner diameter.
Keep in mind that bigger hoses weigh more, which will affect handling of your tool. On spray guns in particular, using a light hose will increase the user’s dexterity.
If you swap hoses regularly, the diameter of all hoses should match. If the hoses do not match, the pressure at the tool will change wildly as one hose is swapped for the other. A quick adjustment at the regulator will fix the problem. We measure air hoses by their internal diameter (or I.D). Simply speaking, the larger the hose I.D, the more air it’ll be able to carry. While the external diameter of air hoses will vary wildly depending on the quality of the hose and the material it’s made from, common internal sizes of air hose are 6mm, 8mm and 10mm internal diameter.
The rule of thumb when picking your hose I.D is the higher the CFM requirement of your air tool, the larger the diameter hose you’ll need. Hand held tools such as spray guns and nailers tend to require 1-3 CFM and will work perfectly well with a 6mm hose. A heavy duty impact wrench is more likely to require 6 CFM+, so you’ll probably require an 8mm or 10mm hose to run at full capacity.
The diameter of a hose will affect the overall weight of the line quite dramatically. Adding a couple of extra millimetres to the hose I.D. soon adds up over a distance. For small handheld tools, where dexterity counts, choose a 6mm hose.
The material the hose is composed of will determine its performance. Each material performs differently under differing circumstances. The air delivery capacity is the same for all these materials. Let’s take a look at the different materials.
Rubber hoses are the traditional choice. Most hoses in use today are made from rubber.
Rubber hoses lie flat, won’t kink at all, and are easy to coil. They remain flexible in freezing conditions, but do not perform as well as polyurethane hoses in this environment.
The big drawback of rubber is its weight. Rubber hoses are by far the heaviest hoses in this lineup; 30-40% heavier than the closest competitor. Weight does matter when you are working on special projects such as roofing. Rubber hoses have a tendency to slide off the roof under their own weight. Lighter hoses make roofers work faster.
In the shop rubber hoses are a star. The weight is not much of an issue since all work happens on a workbench. The hose stays exactly where the user places it, and it’s easy to coil and put away at the end of the day.
Strictly speaking, there are two distinct types of hose;
- first, there’s the standard air hose that lies flat, without bends or coils. You can loosely wrap the hose into loops for storage. Alternatively, you can mount them in a hose reel that can be wound up with a crank handle and mounted on a wall.
- the second is a recoil hose that has lots of small, regular twists, similar to traditional telephone wires. The coils are tensile and have a memory, so when you let go of the hose, it shrinks back for easy storage.
Choosing between the two is a matter of preference and individual application.
· lies flat
· does not kink
· commonly available
· mediocre cold weather performance
PVC hoses are the budget champions. They do coil and kink, but not as much as other materials. With some patience a PVC hose can be made to lie flat on the floor. Cold weather performance is poor.
All of this can be forgiven, because PVC hoses are the cheapest hoses in the market. You’ll get reasonable performance for very little money. Most portable air compressors sold today ship with PVC hoses.
If you only use your hose occasionally, a PVC hose may be the right choice for you. Due to its lower weight a PVC can outperform a rubber hose. A contractor, who spends 8 hours a day on the jobsite, is probably better served by other types.
· good enough for many situations
· coils and kinks
Nylon hoses are significantly less durable than the other materials. Nylon also kinks very easily. You’d think that these properties eliminate the material for selection; think again.
Nylon can be coiled like a spring. It is also the lightest material in this lineup by a wide margin (1/8 of rubber). These properties make it ideally suited for coil type air hoses.
Nylon coil hoses are commonplace in factories and assembly lines. Hanging from the ceiling the spring like feature of the hose acts as a built in hose reel. Being light weight with most of the remaining weight suspended from the ceiling, a well placed coil can create a weightless feeling at the tool end. None of the other materials can match this property.
On the job site Nylon hoses are a leak waiting to happen.
· maintains its tension, great for coils
· placed on the ceiling a coil can create a weightless feel at the tool
· kinks very easily
· less durable than the other materials
Polyurethane hoses are the new kid on the block. Engineered to outperform rubber in some scenarios, polyurethane hoses offer excellent cold weather performance well into the minus range at a weight that is half that of rubber. Polyurethane hoses are a favorite with roofers who have to span large distances and work off the ground.
Unfortunately these excellent properties come at the expense of flexibility. Polyurethane hoses have a tendency to kink, twist, and coil. A Poly hose will also stick to itself due to the inherent properties of the material. The material is also vulnerable to certain solvents. Paint crews working with oil type paint thinner need to be careful around polyurethane hoses.
· best cold weather performance
· much lighter than rubber
· kinks easily
· sticks to itself
· vulnerable to some solvents (painters beware)
Handling during use
Before using the hose first fully unroll it and check that the hose has no turns or kinks. During use bear the following points in mind:
- avoid sharp bends immediately behind the coupling. Make use of saddles or anti-kink coils if this bend cannot be avoided.
- avoid twisting
- avoid pulling over or along sharp objects and scuffing over rough floors
- with a suspended hose always take account of the loads on the hose and couplings as a result of their own weight and the contents
- use protective planks when crossing a roadway
- do not use higher operating pressures than advised. The working pressure is calculated for a constant pressure so not pressure impulses
- use the correct hose for the correct applications!
Intensive use or application in heavy conditions require regular inspections. Place the outstretched hose on a clean, dry surface. Inspect the outside wall of the hose without it being under pressure. When one of the following effects can be observed the hose must be replaced or shortened for safety reasons:
- cuts or cracks in the wall, whereby the inlays are damaged or exposed
- wear on the outside wall so the inlays are visible
- blistering in or the detachment of the outside wall
- shifted hose couplings or fastenings.
Depending on the nature of their application hoses must regularly be pressure tested. A rule of thumb with use for chemicals is that a pressure test must take place at least every sixty days. The hoses are tested at a pressure no greater than 1.5 times the maximum working pressure during use. Testing at the maximum test pressure already takes place at the manufacturer. Frequent testing at a too high test pressure is destructive and can result in the connection between the inlays and the hose being broken.
The pressure test must take place with water with the hose outstretched. Allow the pressure to increase to 1.5 times the normal operating pressure. Then inspect the hose and couplings for tightness. After testing the hose must be carefully cleaned.
Air Hose Increase the life of an air hose by following these preventive tips:
1. Oil and air hoses do not mix. • Oil can get into the hose from the air compressor or from lubricating various air tools. • Wipe excess oil from the hose cover. • If oil damage is possible, choose a hose that has a tube and cover that is designed to withstand oil. RMA Oil Classifications
• Class A = High Oil Resistance
• Class B = Medium-High Oil Resistance
• Class C = Limited Oil Resistance
2. Heat • Keep hose away from radiant heat sources like steam pipes, heaters, exhaust vents and radiators.
3. Ferrules • Never use a hose with a crushed ferrule. • Crushed ferrules can blow out causing bodily injury and property damage. Always replace a crushed ferrule before use.
4. Storage • Always relieve excess pressure. • When finished using an air hose, shut the air off at the compressor and relieve excess pressure at the air tool. • Do not run over air hoses. • Running over hose causes a sudden increase in air pressure which can damage the hose.
5. Reversing • Reverse the hose end-for-end at regular intervals. • Reversing the hose distributes exposure to heat, oil and points of greatest flexing