Hose clamps, by definition, are fairly simple – they consist of a flat or round material that wraps 360 degrees around a hose, compressing down onto a rigid shank inside of the hose. This shank serves as a connection fitting at the end of, or in-between, hose lengths. Hose clamps are usually made of metallic or plastic material and can be formed in band (flat) or wire (round) profiles. The clamp will include a means by which to tighten up, achieving the necessary compression around the hose fitting so that it does not leak or slip off.
From here, the world of hose clamps opens up into a massive variety of options. There is so much overlap between hose clamp options that usually multiple styles can easily apply to the same job. Given the volume of choices, we’ve developed our own check list for selecting the right hose clamps, which we’ll share below.
Selecting Hose Clamps – A Step-by-Step Process
Step 1 – Select Firm or Soft Hose
A soft hose material will be more susceptible to cracks and tears at the clamp location than a firm hose material. Knowing your hose material stiffness and thickness will give you insight into if your clamp should be a more forceful type for clamping down on rigid hose sidewalls (with narrower widths and higher torque loads), or a gentler type for lightly gripping soft sidewalls (with wider widths, lower torque loads, and rounded corners).
Step 2 – Look Up Hose Manufacturer’s Recommendations (Pressure and Temp Ratings)
Interestingly, hose clamps are not themselves rated for pressure. The pressure rating of a hose assembly is a function of the hose material, the clamping force (or torque), the fluid properties, the fluid temperature, and the hose end fitting, considered altogether. For this reason, you’ll want to defer to the hose manufacturer or supplier to state what hose clamp styles will work best for your application. In absence of a manufacturer’s spec, start with hose clamps chosen by firm or soft hose material applicability and perform pressure tests to confirm suitability before placing into service.
Step 3 – Select Clamp Profile
At the highest level, we select a flat or round profile for our clamp. For example, a wire clamp with a round profile might be the best choice for a soft, thin hose, as it presents no sharp edges that could damage the hose. In contrast, a thick, high pressure hose could benefit from the ample clamp surface area and high torque of a flat profile bolted band clamp.
Step 4 – Select Diameter
Hose clamps are most often selected by a diameter range, which states the smallest and largest diameters that the clamp can adjust around. You’ll generally want to select a hose clamp which has your hose’s outside diameter falling about midway through the clamp’s adjustment range. Remember that most hoses are measured by their inside diameter or ID, and you have to consider the thickness of the hose in figuring the outside diameter. For example, a 1.5” PVC 70 PSI hose has an outside diameter of 1.83”. In turn, we could select a hose clamp with a clamp range of 1.4375” to 2.00” to fit this hose. Selecting the diameter will usually eliminate some drive and material options from your available choices, hopefully making the following steps a little easier!
Step 5 – Select Material
Hose clamps come in a small range of materials, thankfully. For industrial applications, stainless steels and plated steels are most common. Stainless options can include a host of alloys such as 17-7, 303, 305, 316, 430, and more. Plated steel options can include copper, galvanized, PVC, and zinc plating. Less common materials include a variety of plastics, aluminum, rubber, or plain steel. When choosing a material, consider factors such as corrosion resistance, fluid temperature, ambient temperature, UV exposure, shock / stress / vibration, reliability, appearance, availability, and cost.
Step 6 – Select Clamp Mechanism
There are a host of clamp mechanisms, such as worm drive, screw/bolt drive, pinch/ear points, wire tension, spring clamps, snap/rachet grips, buckle bands, quick-release drives, and even multi-point drives. With so many options, we aim to narrow things down with a few questions:
- Need quick adjustment without tools on low pressure applications? Spring, snap, and tension drives would work well, but keep in mind that many of these types are single-use.
- Need quick adjustment with or without tools on higher pressure applications? Look for quick-release thumb, screw, or bolt drives.
- Need general purpose, adjustable and reusable clamps for standard pressure applications? Try a worm drive or screw drive.
- Need general purpose, low cost and non-reusable clamps? Go for an ear or pinch clamp.
- Need high pressure, robust and resilient clamps? Go for the highest grade of screw or bolt drives (reusable), or buckle band clamps (non-reusable).
- Have a large diameter hose or duct application, or a connection that needs precise even tensioning? Try a multi-point clamp, which has multiple screw points around the diameter of the clamp.
A Note About Specifications
Hose clamps do not generally fall under a standardized industrial or structural specification program, as we tend to find with other fasteners. One agency (the Society of Automotive Engineering or SAE) does at least offer a standard for the design and construction of clamps within the automotive industry, described as “applicable to OEM coolant, fuel, oil, vacuum, and emission systems”. This standard is known as SAE-J1508, and specifically excludes any application guidance – it contains hose clamp fabrication specs only.
Some application guidance can be found in separate documents SAE-J1610 and SAE-J1697, as well as in another agency’s publication, the American Trucking Association’s Technology and Maintenance Council TMC-RP-332. If you know your application to fall under automotive regulations, you’ll start the above process by either selecting the suggested clamp per the above specification documents, or by looking for ‘SAE-J1508 compliant’ on the hose clamp’s description.
For those applications which do not fall under automotive regulations, but would still benefit from additional technical information around selecting hoses and hose clamps, we can refer to a Purdue University publication titled ‘Hose Selection Guide’ that can be found here. Or, please contact us with your project requirements, and we will obtain technical data from one of our premiere hose or hose clamp manufacturers’ engineering departments specific to your application. For more information, please visit our website here or contact us here.
About E&T Fasteners
With sales and support teams spanning the Continental US, E&T Fasteners is here to serve your hardware, fastening, and component needs both domestically and internationally. We are a stocking distributor of metallic, plastic, and exotic alloy fasteners, backed by our technical staff directly experienced in your unique applications. We can assist your specifying and selection efforts, providing engineered solutions, record-fast lead times, and stellar customer service from quote through delivery. Please let us know how we can help!