BlastOne

How Does Using the Correct Hose Size Effect your Tank Project?

Productivity depends on the volume and pressure of the air passing through the nozzle

Where production is slow, there’s usually not enough air volume (cfm) and pressure (psi). A larger compressor will provide more air to support a larger nozzle, and a larger nozzle gets the job done faster. But the big question is: "What do you have in between?"

The Air Hose (Bull Hose)

Often when you are blasting on a tank project you will need to use long runs of air hose (bull hose) and blast hose, sometimes as much as 60-90 meters (200-300 feet) or more. It all depends on the accessibility of the site and how close you can get your blasting equipment to the tank.

Every time you increase the distance between the air compressor and the blast pot you are increasing the distance the air has to move through the hose and this increases the loss in blasting pressure. Likewise if you increase the distance between the blast pot and the nozzle on the abrasive side you are not only moving air a lot further but also the abrasive. It becomes quite a struggle for the air to propel the abrasive along without it dropping out of the air stream and clogging.

Three Key Factors to Remember:

  1. Shorter hoses are better to maintain maximum pressure.

    Keep your air hose and blast hose lengths as short as possible. Position your compressor as close to the blast pot as possible to shorten the distance the air has to travel and it is even more important to keep your blast pot as near to your blasters as you can. This keeps the pressure drop along the hoses to a minimum.

  2. Bigger Inner Diameter(ID) hoses are better to reduce friction and pressure loss.

    When it comes to hoses, bigger is always better. Running large ID hoses in your blast system reduces the friction and the pressure loss caused in smaller, more restrictive sizes. If you have the correct size and length blast hose, you will keep your pressure up and keep your abrasive flowing all the way to the nozzle for better performance, consistent quality surface profile, finish faster, use less abrasive and create less dust.

  3. Get the most productivity from your bull air hose, use a bull hose to supply air to your pot.

    Double your blasting rate by simply updating your air supply hose. Big nozzles need big hoses. When you are blasting with a nozzle any larger than a 7/16” (no. 7), you need to supply your air to the pot in a 2 inch (50mm) ID bull hose. Any smaller air delivery hose than this will simply be choking the air supply and decreasing your blasting potential.

Important Note: Check your hose fittings as it is no good having a nice big bull hose to supply air to your blast pot if you’ve still got hose fittings or pipe fittings that have a smaller bore than the ID of your hose.

undersized-air-supply-hose.jpg
Low Pressure
normal-air-supply-hose.jpg
High Pressure


The Blast Hose

Correct blast hose sizing is critical for productive and efficient blasting. Improperly sized hoses will have a major effect on your blasting production, abrasive consumption, the surface finish, surface profile and the wear on your blasting equipment. It is very important to size hoses correctly for efficient blasting.

Rule of Thumb for a Blast Hose

Minimum size: 3x the blast nozzle orifice.
Maximum size: 5x the blast nozzle orifice.

Hose Selection Guide for Blasting at 100 psi Nozzle Pressure using Garnet Abrasive

Nozzle Number No. 4 No. 5 No. 6 No. 7 No. 8
Nozzle Size 1/4" (6mm) 5/16" (8mm) 3/8" (10mm) 7/16"(11mm) 1/2" (13mm)
CFM at 100 psi 103 158 229 312 407
Air Hose ID - minimum 25mm (1") 38mm (1 1/2") 38mm (1 1/2") 50mm (2") 50mm (2")
Blast Hose ID - minimum 20mm (3/4") 25mm (1") 32mm (1 1/4") 32mm (1 1/4") 38mm (1 1/2")


The Whip Hose

You need to be a muscle man to continually hang onto some of those large blast hoses all day. By ensuring the blast hose is four times the diameter of the nozzle sure helps keep the pressure up, but it becomes very hard to continually hold. We recommend you fit a 6m (20ft) SupaLife whip hose between your blast hose and nozzle. This special hose is made of high quality rubber to maintain life, but with thinner walls to make it lightweight and flexible. The SupaLife whip hose has a large bore so you don’t lose pressure to the nozzle. Your operator will find it easier to blast, much less tiring on the back and easier to get into tough spots.

Don’t use a smaller size blast hose as a whip hose. - You’ll just choke the system up.

Rule of Thumb for a Whip Hose

The ID of your whip hose should be the same as your blast hose.

air-supply-hose.png
The Right Pressure

Comparative Percentage Host Area Reduction
Main Blast Hose Size Whip Hose Size % of Reduction of Internal Area
1 1/2" (38mm) 1 1/4" (32mm) 31%
1 1/2" (38mm) 1" (25mm) 56%
1 1/4" (32mm) 1" (25mm) 36%
1 1/4" (32mm) 3/4" (19mm) 64%
1" (25mm) 3/4" (19mm) 44%