Why Use Steel Braided Hose?

STAINLESS STEEL BRAIDED HOSE

What is stainless steel braided hose?

A hose consisting of a corrugated stainless-steel core with stainless steel braid, each working together with their own function. While the corrugated stainless hose carries the pressure and has great hoop strength. It needs the tensile strength of the braid to keep it from elongating.

Stainless steel braided hose pressure rating

Every hose has its own pressure rating. There are several variables that effect a hose pressure rating.

🔺Diameter
🔺Hose thickness
🔺Braid design
🔺Corrugation shape
🔺End fittings used.
🔺Temperature

Always make sure the hose you select has a pressure rating that will handle the application.

Stainless steel braided hose bend radius

The bend radius of a hose is the minimum radius a hose can be bent in without compromising its integrity. The bend radius is used to determine the length of hose (life length) needed for a specified movement. There are generally two types of bend radii indicated for a hose and braid product. A “Static” bend radius used to determine hose length for an offset in the piping that will not see movement. The other bend radius is the “Dynamic” bend radius, and this is used to determine the length of hose needed for application that will see cycling movement such as in a HVAC system.

Always used the bend radius of the specific hose you will be using. Each hose has its own bend radius.

ISO 10380 should be used to determine the bend radius.

What is live length when referencing stainless steel braided hose product?

The live length of a hose assembly is another way of saying the length of hose required for a given movement. The live length is the length of hose between the braid collars (aka braid sleeve) as shown below.

The braid collars (sleeves) serve two functions. First, they act as a clamp to keep the hose and braid tightly together for the cap weld. Second the braid collar acts as a stress relief point for the heat affected zone of the cap.

Why Use Corrugated Stainless Steel Braided Hoses?

Corrugated stainless steel braided hoses incorporates time tested and proven technology that have several advantages over rubber hoses including:

🔺Higher temperature rating than rubber flex connectors
🔺Higher pressure limits than rubber flex connectors
🔺OK for outdoor applications
🔺Longer life than rubber
🔺Easily customized

Metal hoses are also available with a wide range of end fittings:

🔺Flanged, including plate, raised face, and weld neck
🔺Thread
🔺Grooved
🔺Weld end
🔺Sweat
🔺Specialty fittings as specified.

What does it mean when a hose is “braided”?

Braid used with corrugated stainless steel hose has two functions.  The first is to restrain the hydrostatic end load of the hose under pressure.  The second is to restrain the hose from squirming under pressure and stay flexible.  The braid basically acts like a “Chinese finger trap” around the hose.

Braid is available in two styles: single braid and braided braid, shown below.  Single braid is made up of groups of wires called carriers or bands.  Braided braid is made up of wires braided together to form the carriers or bands.

 

Standard Braid
Braided Braid

Braid is described in the following format, 72 x 8 x .020 where 72 is the number of carriers or bands in the braid, 8 is the number of wires per carrier, and .020 is wire diameter.

Braided braid is described with the same format but with brackets.  For example, 96 X (13 X .025)

The pressure rating of a hose and braid assembly are dependent on several factors that include:

🔺Hose design (shape of corrugations)
🔺Hose thickness
🔺Number of braid wires
🔺Diameter of braid wires
🔺Braid angle (the angle that the braid wires run around the hose)
🔺Braid coverage (how much of the hose is covered by braid)
🔺Material of hose and braid

What are braided hoses used for?

The list of applications for hoses is just about endless.  The reasons for needing hose and braid products can range from making up for offsets in the piping to compensating for thermal / seismic / building movement.  Some of the most common includes:

🔺Heating and cooling water systems.
🔺Domestic water.
🔺Steam and condensate systems.
🔺Natural gas lines.
🔺Fire sprinkler piping.
🔺Refrigeration lines.
🔺Exhaust lines
🔺Vent lines
🔺Compressed air.
🔺Medical gas.

Always consult Metraflex to review your application. We offer Delegated Design services and are happy to help.

How Long do Stainless Steel Braided Hoses Last?

A properly installed and applied hose and braid product should be considered a life of building product that will last 20 years.

However, there are several factors that can adversely affect the life of hose and braid products:

🔺Corrosion.  There are several material options available for the hose, make sure that the proper hose material is selected for the application.
🔺Erosion.  For high velocity applications a liner can be used to protect the hose.
🔺Excessive movement.  This can be easily avoided by ensuring the proper product was selected and installed.
🔺Excessive vibration.  For some high movement applications longer hoses are used.  For some high frequency applications, a rubber connector may be preferred.
🔺Physical damage

 

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