Guide to Hose Sizing

A hose is a flexible, reinforced rubber or thermoplastic conduit that is used to convey pressurized fluid within a hydraulic or process system. These hoses are often reinforced with several material layers to withstand the required pressure of the system it is being used within.

One of the most fundamental considerations when selecting hose is sizing.  If the hose is too small of inside diameter, pressure losses could be high and excessive flow-rate will create heat which leads to damaging the hose inner tube and possibly creating flow erosion of the hose’s tube.  This can lead to damage of seals, clogged pumps, valves, and filters as well as failure of the hose itself.  If the hose is too large of inside diameter, the volume of fluid contained will be greater than needed for function of the equipment and routing of the hose may be difficult.  Additionally, the costs of the larger hose assembly and connections may be higher than actually needed.  Response time will also be delayed on hydraulic systems if the hoses are too large.

As you can see, proper selection of sizing is very important when specifying a hose for a particular application.

Hose Sizing Metrics

Hose size is determined based on the inner diameter (I.D.), along with the flow rate of fluid within the system.

Inner Diameter

Hose sizes are designated based on the inner diameter of the hose, which is the measurement of the straight distance between the two furthest points on the inner surface of the tube.  Virtually all hoses made globally are made on inch sizes even if given a metric size designation.

Most hoses used in North America are designated in inches of ID.  For industrial hoses, it is most common to see the size in direct terms of the inch size.  For example, a 3/4” measured hose ID will be designated as either a “3/4” or in terms of decimal size “.75”.   The metric nominal equivalent may also be referenced as well, but keep in mind that this just a reference in most cases.  In the vast majority of common hydraulic hoses, the I.D. measurement is divided into 1/16” increments known as the “dash size.”  For example, a hose measuring 3/4” ID will be shown as a “-12” coming from the numerator of the fraction of 3/4″=12/16”.  A 1” ID would be 16/16 or a -16, and so on.  There are notable exceptions to this designation namely SAE 100R5, 100R14, and certain other hoses used in airbrake and refrigerant applications.  These are based on tube connection ID sizes and consultation with cataloged information will be helpful to properly understand the designation for any of these hoses.

Outer Diameter

The outer diameter (O.D.) of the hose includes the entire cross-section of the hose. Although the O.D. can be used to ensure the hose fits within the allotted space, it has no direct impact on pressure loss and flow calculations within systems.

Length

The hose size must also take into account the maximum distance between the two end points of the hose. As hose length increases, so does the friction losses between the fluid and the inner surface of the hose, which reduces pressure inside the system. You should therefore consider the hose length when calculating system pressure requirements.  Going slightly larger ID will reduce the pressure loss (also known as pressure drop).

Flow Rate

The flow rate (expressed as gallons per minute or liters per minute) or velocity (expressed as feet per second or meters per second) of the fluid moving within the system is the key to understand when sizing the hose for proper performance.  The maximum system flow rate is determined primarily from the ratings of the pump used.  Pump data may be found on the pump manufacture tag, system specifications or from the pump manufacturer’s catalog or website.  Sometimes this is expressed as “pump curves” which are based on several variables including speed at which the pump is being driven.

Once the system maximum flow rate is established, use the nomograph supplied in the Jason hose product catalog that will allow simple determination of appropriate selection of the proper hose size for best performance and durability for the given flow.  Note that as indicated in the nomograph, hoses used for suction (pump intake) must be sized larger than those for the output side of the pressure (pump outlet).

Selecting the Proper Hydraulic Hose Size

To ensure the best selection for your hose options, industry professionals adhere to the S.T.A.M.P.E.D. system, which stands for size, temperature, media, pressure, ends, and delivery.

Size

The inner diameter of the hose must be correctly sized to ensure proper fluid flow within the system. Too much flowrate by the hose being too small of ID can cause inconsistency, internal damage, and fluid leaks, while too large of hose can compromise the system’s response output.

Temperature

When selecting a hose for your system, it is critical to determine the operating temperature range of your equipment. Some materials contract, expand, or fail when exposed to high or low temperatures and thermal fluctuation. To avoid these complications, select a hose material that will operated within the expected equipment temperature ranges to be encountered.

Application

Different applications require different hoses. Many hoses are custom-built assemblies made to meet specifications for a prescribed application need. Consider the system configuration, fluid type, and product routing, and hose orientation to determine the best hose for the job.  Normally, if the hose is to be used as a replacement of an existing hose, replacing with the same type/rating of hose is a good choice for similar durability and performance expectations.  Consult the product catalog for basic information and seek application assistance from Jason if there are any questions.

Media

A wide variety of materials can be conveyed using hoses, so you must consider the potential for physical or chemical reactivity between the fluid medium and the hose material. If an unsuitable material is used in the hose or its fixtures, it can damage the system or lead to failure of the hose and potentially create hazardous conditions due to the failure.  Compressed gases require specially designed and manufactured hose constructions.  Some materials can damage the hose reinforcement and even the end fittings and seals all which may lead to sudden and catastrophic failure.  Understand the application and check to verify compatibility if there are any questions or concerns.

Pressure

Your hydraulic hose will need to withstand the working pressure of the application, as well as any additional pressure that could be caused by fluctuations within the system.  Careful consideration of the specific application must be made to assure the hose is properly selected for best durability and safety.

Ends

When selecting your ends or couplings, consider the size, material, and application. Fittings come in a dizzying variety of styles, orientations, and attachment methods to meet the particular needs of every system.  Each connector type has many attributes as well as limitations on ratings and resistance to leakage and pressure.  Consult Jason for more information.

Delivery

Timely and reliable delivery is an often-overlooked necessity when selecting the proper hose. Whether you need special packaging, unique shipping, certification, testing, or tagging, Jason Industrial will help you get the product you need, when you need it.

Quality Hoses From Jason Industrial

Accurate hose sizing requires a combination of complex calculations and industry knowledge. Even if you’re experienced in the field, it’s a good idea to consult with a manufacturing technician to get the best tools for your project. Selecting the wrong hose for your custom equipment can cause system failure and unnecessary expenses, but a professional consultation can ensure the best possible outcome.

The experts at Jason Industrial have the knowledge and equipment necessary to ensure you have the best choice of hose for your application. For help finding the best hose for your project, contact us today to request a quote.

6 Tips for Industrial & Hydraulic Hose Maintenance

Preventative maintenance is the key to ensuring your industrial and hydraulic hose systems have a long, functional lifespan. Along with standard operating procedures, consistent preventative maintenance efforts can keep your operators and managers apprised of the condition of each hose in the facility. Inspecting the hoses, replacing failing or worn components, maintaining an active data log, and having a steady inventory of key components are essential elements of every preventative maintenance plan. These action steps take aim at ensuring long-term optimization and cost-effective system management.

Incorporate these six tips into your preventative hose maintenance plan.

1. Visually inspect the hose and fitting.

Visual inspections are one of the most important—and one of the simplest—steps of preventative maintenance. Regularly inspect the hose system and its fittings for damage, disrepair, or signs of unusual performance problems on a daily, weekly, or monthly basis as appropriate for your application.

We recommend compiling a list of signals that trigger a complete shutdown and hose assembly replacement so your employees can quickly mitigate problems. Those signals should include:

  • Leaks in the hose or around the fittings
  • Fittings displacement or slippage
  • Damaged fittings, including cracks, corrosion, and other visible damage
  • Damaged hoses, including signs of cracks or charred surfaces and unusual hardness or stiffness
  • Kinks, twists and flattened or crushed portions in the hose
  • Damaged covers, including cuts, abrasions, blisters, and cracks, especially if the damage exposes the reinforcement (which requires replacement as soon as possible)
  • Loose, soft, or degraded covers

Keep in mind that no hose should ever be repaired or reused as damage and deterioration of the hose may compromise its ability for use at its original design capability.

2. Track the lifecycle of each hose.

Each industrial and hydraulic hose—and its fittings—has a known expected lifespan. Each end application is at least somewhat unique and requires consideration as to how long the hose assembly should last.  Ask your manufacturer or supplier about that lifespan and the ideal interval for inspections and tune-ups. Tailor the preventative maintenance schedule to the individual components to allow your facility’s inspectors to perform efficient, optimal maintenance. At each stage of the lifespan, look for signs of cuts, kinks, corrosion, or deterioration that match the life stage of the part. We recommend that this be documented in a log of the part’s condition over time. Your facility inspectors can then monitor for increases in damage and see trends in performance.  Strongly consider permanently tagging or other suitable means of marking the hose assembly.  This will also assist in signaling when a hose should be inspected and replaced.

3. Perform functionality tests.

Test each hose system by operating it at its maximum rated working pressure and checking it for leaks or problems. During this test, make sure any system surges also are below the maximum permissible pressure and that personnel maintain a safe distance from the equipment in the event of a malfunction.

Never inspect a hose by being in direct physical contact with a hose under pressure.  Fluid injections can cause severe injury. 

4. Establish consistent replacement intervals.

Even with good preventative maintenance and optimal system operations, parts of the hose system will break down over time. The elastomeric seals, for example, will start to harden, wear, or turn brittle due to both age and frequent exposure to heat and pressure. Replacing these parts anytime the hose is removed helps keep the system as a whole in good condition and doesn’t require unscheduled downtime for troubleshooting and repairs. It prevents failures that could result in injuries or loss of production.

5. Analyze the data.

During each step of your facility’s preventative maintenance program, keep a running record of the assembly’s condition, any parts replaced or repaired, and even that regular inspections occurred without the need for adjustment. All of this data allows your company to monitor the long-term performance of the system and see if the system is performing as expected. Analyzing the data also can help your company determine if it’s time for a new design or system.

When properly equipped, destructive testing, or testing replaced parts to determine how much strain or continued use they can handle, is also a profitable analysis that can help your company reconfigure replacement schedules.

6. Be prepared with spares.

As opposed to having to turn off the machines and cause delays for known or anticipated repairs because you don’t have the parts on hand, maintain an inventory of spare parts. A smart analytics system, combined with your preventative maintenance data, can recommend the right quantities of which components to keep on-site for fast replacement. Along with an in-house inventory, you can order replacements in preparation for scheduled parts replacement tasks and streamline the entire process.

Contact Jason Industrial for Hose Supplies and Accessories

At Jason Industrial, we supply rubber and thermoplastic industrial hoses. We also supply the couplings, fittings, and accessories our clients need to keep their entire hose system in good repair throughout its lifespan. We’re proud to serve an extensive number of industries with hoses and parts tailored to a wide range of applications. Contact our team today to learn more or request a quote to start your order.

How & When to Replace a Hydraulic Hose

In hydraulic systems, hoses carry pressurized hydraulic fluid to or from pumps, motors, valves, actuators and other system components. Due to their critical function, the hoses employed are designed and constructed for suitable flexibility and durability. They must be flexible enough to bend in and around the confines of equipment, fit into tight spaces and may span long distances while being durable enough to withstand the high operating pressures and temperatures. For these reasons, they are generally made from a combination of multiple layers of materials—such as elastomers, fluoropolymers, thermoplastics, textiles and metals.  Typically, hydraulic hoses have an inner lining or tube made of rubber or thermoplastic, braided or spirally applied reinforcement layers of textile yarn or wire and a cover also made of rubber, thermoplastic or braided material.  All of these are uniformly bonded together as one unit.  Finally, for a hydraulic hose to be useful it requires suitable connections with hose fittings (permanent or reusable type) designed to attach to the hose to allow full utilization of the hose’s rated pressure and performance for maximum service life.  It is vital to achieving this maximum acceptable service life and safe use that only manufacturers matched and approved components must used together and assembled to their recommendations.  Mixing/matching of hose components outside of this recommendation can lead to unsatisfactory performance and disaster.

While hydraulic hoses are highly durable, the pressure cycles they experience through normal operation and natural degradation will eventually lead to failure. If hose failure occurs unexpectedly, it can result in employee injury, property damage, expensive cleanup, wasted production, unscheduled downtime and increased material and labor costs. With these consequences in mind, most hose experts recommend a proactive rather than reactive approach to hose replacement—i.e., replacing the hose assembly once it nears the end of its safe and useful life span but before it fails—for the sake of safety and cost savings.

Given the durability generally demonstrated by modern hydraulic hoses, it can be challenging to know when it’s time to replace them. Sometimes there are obvious signs that a hose has begun to fail, but that’s not always the case. In the following article, we discuss when and how to replace hydraulic hoses.

What Is the Typical Service Life of a Hydraulic Hose?

The Society of Automotive Engineers (SAE) has generally set the standard shelf life of unused bulk rubber hoses to ten years from their date of manufacture when properly stored. However, there are many factors that influence the actual working or service life of a hydraulic hose, such as the type and temperature of the fluids, operating pressure and flow, static or dynamic conditions and environmental conditions. While the hose manufacturer or distributor can provide insight into the expected working life when in doubt, replacement should not be delayed if the hose is showing any signs of wear or degradation.  Most hydraulic hoses are designed to pass the cyclical impulse pressure requirements at specific pressure levels above the rated working pressure, temperature and bend radius.  This qualification testing requires the use and assembly with the properly specified end fittings attached to the hose for a number of cycles.  For example, most two wire braid hoses require a successful testing of a minimum of 200,000 pressure impulse cycles, while most wire spiral hoses require at least 500,000 cycles.  This is why wire spiral hoses are normally considered longer service life hoses for equipment running lots of pressure surges within the hydraulic system.

You must keep in mind that every application is different and no manufacturer can predict with accuracy a service life for a particular situation without in depth knowledge of all parameters.  The equipment designer bears this responsibility for a given system.

Generally, if the service life of a hose has proven to provide acceptable durability, replacement with the same or better rated hose should also provide similar life.  The branding on the hose can usually provide the rating such as the manufacturer’s part number and/or the SAE or ISO ratings.

Factors Influencing the Service Life of Hydraulic Hoses

As indicated above, the actual working life of a hydraulic hose depends on many factors. Some of the considerations to keep in mind when assessing how long a hose assembly may provide acceptable service life include:

  • Size: Hydraulic hoses differ in size depending on the anticipated flowrate needs of a system. It’s important to be aware of the limitations of the hoses employed to avoid exceeding their operating capacities. Excessive velocity will damage the inner surfaces of the hose’s tube and other system components may be damaged from the tube debris. Excessive flowrate will also raise the temperature of the hydraulic fluid due to friction.  Using a simple nomograph provided by the hose manufacturer provides guidance in safely sizing the hoses for hydraulic system’s pressure and return circuits once the pump output flowrate is selected.  Normally, return hoses must be sized larger than pressure lines (see manufacturer’s nomograph).
  • Temperature: Typical rubber hoses are designed for operating temperatures ranging from -40° F to 212° F. Certain other hose materials can provide safe performance up to 250°, even 300° F. PTFE tubed hoses can safely be used up to 450° F.   Hydraulic fluids or ambient conditions outside of this range can lead to premature failure. Higher temperatures can lead to the hose becoming hard, brittle and cracked, while lower temperatures result in the hose becoming cracked without losing its softness or flexibility.   The cooler the hose fluids can be usefully used at well below the rated maximum, the longer the hose will be able to not experience material degradation.  Care must be taken to properly route and shield hoses away from external heat sources such as engine manifolds which can quickly reduce the life of the hose and often lead to fires.
  • Pressure: In addition to having set operating temperatures ranges, hydraulic hose assemblies have maximum rated working pressures. If the system pressure exceeds beyond this point, the hose may suffer permanent damage and/or fail. For this reason, it is recommended to use hoses rated for a few hundred psi over the system’s maximum working pressure to avoid surpassing the hose’s rating. The integration of quick acting pressure-relief valves can also help minimize the risk of excessive pressure spikes. Pressure spikes create cumulative damage within the hose and adds up over time and eventual likelihood of hose failure.
  • Application: Each hose is designated for a specific set of system functions and duty cycles. However, even when used properly, hoses can be damaged by environmental factors related to their application. For example:
    • Hoses used in mobile equipment often rub against other equipment components or even other hoses, which leads to damage to the cover and reinforcement over time. Again, routing of hoses near engine exhaust components can quickly damage a hose from the high temperatures.
    • Hoses used in indoor environments may be exposed to higher temperatures, especially when situated near furnaces or ovens, which can lead to thermal damage.
    • Hoses used in vertical installations experience more stress than those used in horizontal installations.
    • Hoses used in applications with cyclical pressure loading can move due to up to 3% change in length. Hoses have to be routed and design length chosen to account for this movement.  Any such application should have suitable inspection of the hose to see if there is degradation of the hose itself or the connections leaking.  Any rotation of the fitting swivel under use will lead to leakage or ultimate failure unless the connection is made using a “live swivel” intended for dynamic swiveling.
    • If the hose is installed on components that experience movement (such as a pivoting hydraulic cylinder) routing is very important to allow for proper length for flexing and all twisting or bending in multiple planes of the hose should be avoided.

While these conditions may be unavoidable, ensuring the hose is properly installed and implementing protective measures (e.g., hose guards or shielding) can significantly extend the service life of the hose assembly.

  • Fluid: When selecting a hydraulic hose assembly for a system, ensure all of its construction materials are compatible with the chosen hydraulic system fluid. Its compatibility can be determined by checking the Material Safety Data Sheet (MSDS) for the fluid in combination with the hose manufacturers listings of compatibility. Using incompatible materials can damage the assembly and compromise system performance.  Some fluids can easily damage the hose tube and lead to failure, so you must make sure of compatibility with the hose.

Signs Signaling a Need for Hydraulic Hose Replacement

While it is often difficult to determine whether a hose assembly needs replacement, there are some visual cues that indicate it has reached the end of its service life. For example, if the hose assembly has any of the following conditions, it must be replaced:

  • Crushed or distorted hoses
  • Fluid leakage (within the hose length or at the fitting end)
  • Exposed wire reinforcement
  • Significant surface damage (beyond scuffs and small nicks)
  • Kinks (an indication of incorrect routing)
  • Twisted hoses (another indication of incorrect routing)
  • Hardened or blistered cover as well as any signs of the cover softening significantly which may signal a fluid compatibility problem
  • Corroded fittings (white oxidation is normally, acceptable while red rust warrants replacement)

Steps for Replacing Hydraulic Hoses

The replacement process for a hydraulic hose is as follows:

  1. Identify the issue. Verify which hose is damaged before removing and replacing it. Be thorough in assessing the situation to ensure that the repair actually addresses the problem. With this information in hand, purchase a suitable replacement that will provide same or better performance rating.
  2. Assess the situation. Check what system components need to be removed to allow for the replacement of the problem hose.
  3. Prepare the system. Address any components connected to and around the hose to ensure they do not hinder the replacement process. This step must include relieving pressure to avoid the leakage of process fluids, lowering pieces to the ground to prevent them from falling and removing parts to allow for an obstructed view and workspace. Note, at this point it may be useful to photograph a few suitable views of the hose’s routing to assure a replacement is put back in place properly.
  4. Loosen the fittings. Once the hydraulic assembly is prepared for the actual replacement operation, loosen the fittings as required that attach the hose to the machine.
  5. Remove the hose. When the fittings are loosened, remove the hose and pour any residual fluid into a waste container.
  6. Seal the fittings. Before installing the replacement, seal the fittings with a designated fitting plug or rag to avoid further leakage.
  7. Install the new hose. Install the replacement using the proper techniques and reassemble the rest of the system. Refer to manufacturer’s recommendations for details and any applicable torque recommendations.  Consider tagging the hose (see later in this document).
  8. Visually check the installed hose. This will help make sure the installation is proper in routing and connection.
  9. Test the system. Once the hose assembly is replaced and the system is fully reassembled, test the system to ensure there are no leaks or performance issues.

Determine Replacement Intervals

Keep records as to what the inspection of the hoses is showing regarding hose durability and determine what replacement intervals may be needed to assure hoses are replaced before failure.  Tagging the hose when installed, inspection intervals and replacement dates will help in this process.   The goal is to make sure that the hoses are replaced before failure.

Contact the Hydraulic Hose Experts at Jason Industrial Today

All hydraulic hoses will eventually fail. Preventing their failure from affecting equipment or facility operations necessitates proactive measures, as outlined above. For further assistance determining when and how to replace a hydraulic hose assembly, turn to the experts at Jason Industrial.

At Jason Industrial, we have over six decades of experience handling industrial hoses and an extensive selection of hydraulic hose products. These qualities make us the ideal partner for all hydraulic hose needs. To learn more about our offerings and how we can help extend the service life of hydraulic equipment, contact us or request a quote today.

Mixing & Matching Hydraulic Hose and Couplings

As we progress through our introduction of hydraulic hose and coupling products at Jason Industrial, there have been a number of requests for interchange to competitors’ hose and couplings.

The term “interchange” needs to be clarified. No hydraulic hose or coupling is truly interchangeable because each manufacturer produces products that are tailored to their own processes and equipment. This is why mixing and matching is never recommended by anyone concerned about the satisfaction and safety of their customers and end users. Even though a particular hydraulic hose may carry the same SAE, ISO, or EN standard labeling, they are not made to the same tolerances and materials.

The same is true for couplings, perhaps even more so. Nearly every manufacturer has developed their own unique designs customized for their own validated and approved hose products. Additionally, the assembly specifications for crimping these hoses and couplings are unique to each piece of equipment.

Let’s focus on the coupling side of interchange for today’s discussion. Jason currently has three series of couplings for our hydraulic hose products.

  • The JB12 for our 1 or 2 steel braid reinforced hoses
  • The JB40 for our 100R12
  • The JB60 for our 100R13

Other manufacturers may have one series that covers both wire braid and some wire spiral such as 100R12 or even 100R13 (skived). Others may have a series that covers thermoplastic hoses like 100R7 and can be crimped on certain wire braid hoses like 100R16, but not 100R2. While there are many similar examples, the bottom line is always the same: it is never going to be a one to one direct interchange.

So how do you address this when you’re working with a customer who could move to Jason as a supplier? We recommend that you first sort out which hoses the customer is using or wishes to buy. Once you’ve established this list, evaluate the competitor’s couplings to identify an equivalent Jason part to provide the connector ends needed for the hoses we’re offering. This will ensure that the customer will have the correct hose and couplings for their needs when an order is processed.

Think of “interchange” as more of a cross reference for the correct hose and necessary connections. Yes, it can get a little complex, but your Jason team can support you to guarantee the correct products. Don’t be afraid to ask if you need help or have any questions.