What is the pressure rating for Husky couplings and the Anaco standard no-hub coupling?
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Husky couplings are designed for drain, waste and vent, a gravity system. They are not pressure rated. However, Husky couplings conform to the standard ASTM C . Within the standard are “Couplings Requirements and Test Methods”. One of the tests is an Unrestrained Hydrostatic Joint Test. Reference the test method below:
Fill the pipe assembly with water, expelling all air. Increase the hydrostatic pressure at a rate of 1 psi (6.9 kPa) every 30 s until the specified test pressure is reached. The specified test pressure shall be 30 psi for 1 ½ in. through 5 in., 27 psi for 6 in., 15 psi for 8 in., 9 psi for 10 in., and 6 psi for 12 and 15 in. pipe. When the specified test pressure is reached, hold it for 15 min. Any leakage or axial joint movement of more than 0.150 in. shall mean failure.
The Anaco standard no-hub couplings conform to CISPI 310 & ASTM C . The specified test pressure in the standards are 20 psi for 1 ½” – 5”, 18 psi for 6”, 10 psi for 8”, 6 psi for 10”, 12” and 15”. When the specified test pressure is reached, hold it for 5 min.
What kind of deflection can I expect out of the Anaco standard no-hub and Husky couplings?
Husky couplings conform to ASTM C . The deflection range in the standard is 1” per lineal foot. Anaco standard no-hub couplings conform to CISPI 310 & ASTM C . The deflection range in those standards is ½” per lineal foot.
What is the required torque when installing Anaco standard no-hub and Husky couplings?
The Husky couplings are designed to be installed with a pre-set torque wrench calibrated at 80 inch pounds to accommodate the 3/8” hex head screw of the SD and the 5/16” hex head of the HD . The Anaco standard no-hub couplings are designed to be installed at 60 inch pounds. There is a very important torque sequence that needs to be followed when installing the Husky couplings. You can view an installation video by going to our home page and clicking on the installation video.
What is the temperature rating on the Anaco couplings?
The gasket for both the Anaco no-hub and Husky couplings are made of Neoprene in accordance with ASTM C 564. The maximum temperature that neoprene will accommodate with continuous service is 203 degrees Fahrenheit with a maximum intermittent temperature of 212 degrees Fahrenheit.
Are the Anaco couplings fire protection rated?
Questions about the ratings for Anaco couplings for cast iron joints in a firewall have been asked for years with the building code requirements for membrane and through penetrations. There are no problems using Anaco couplings in a rated wall for the code. The material in the wall is cast iron, a non-combustible material and the Anaco couplings have a neoprene sleeve, surrounded by a non-combustible stainless steel shield. Our gasket was tested and passed the 25/50 flame spread requirements. These joining methods have been in use since , and while questions have been raised in the past, these materials will not melt away in a fire and leave a hole in the wall for the fire and smoke to spread.
Can I use an adhesive lubricant on the Anaco couplings?
Anaco does not require or encourage the application of any type of adhesive lubricant with its couplings. However, we know that Black Swan NO-HUB sealant has been used with Anaco couplings in the past without any problems, often been used for hubless systems in cold climates where air testing is the only method allowed. The use of the sealant does not take the place of proper joint restraint. Some codes will not allow any lubricant to be applied to no-hub couplings, so before using any lubricant with no-hub couplings, check the applicable codes for restrictions.
Do I have to grind off the positioning lugs on the fittings to accommodate the Husky couplings?
No. There was only one joining method in for hubless, the standard coupling. The position lug was placed on fittings to show the fitting was installed against the center stop of the gasket. Sizes 8” and larger do not have a lug under the gasket. The fittings are manufactured to CISPI 301 that includes dimensional tolerances for the location, height, width and length of the lug. Fittings that meet the standard will work without any additional installation requirements.
Can I use a Husky coupling to join PVC to cast iron?
With the Husky SD you can join your PVC piping system with cast iron. Husky SD is Tested and Certified to ASTM C the shielded transition standard. Husky is made to provide a better joining method. Standard transition couplings are only 2.1” wide and have 2 bands. Husky SD couplings are 3” wide through 4” and have 4 bands. An identifying transition label is on every coupling for inspection purposes.
Can I use Husky couplings to join my hubless system underground?
Husky SD couplings have been used underground for many years due to its outstanding performance and reliability. But, Husky has now developed the Husky CR for your underground applications. The corrosion resistance found in the new CR is due to the higher grade type 316 stainless steel, highly corrosive resistant. You will also enjoy the same performance and standards as you have from the SD . When coupled with cast iron pipe it will last as long as the system is connected.
Grooved pipe couplings are some of the most important equipment in fire protection, allowing quick and water-tight connections without pipe threads, flanges, or welding. Instead, installers simply butt the ends of pipes together and seal them with a gasket and clamp.
But there are also two kinds of grooved couplings that serve different purposes. Rigid grooved couplings don’t allow much movement and serve as a standard pipe joint. But for situations where some give is needed—specifically, seismic protection of fire sprinkler systems—flexible grooved couplings are the solution.
This article reviews the basics of grooved pipe couplings and details the differences between a rigid and flexible coupling. We also explain when and how NFPA 13: Standard for the Installation of Fire Sprinkler Systems ( edition) requires using flexible couplings for seismic protection.
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Shop our selection of rigid grooved couplings and other fittings for your pipe-joining needs. Looking for flexible couplings? Contact QRFS today for a quote or to place a special order.
Grooved couplings are the fastest way to join pipes. And the technology is simple. Earnest Tribe, the founder of Victaulic, patented the grooved pipe joint in after developing the tech to meet wartime needs. Grooved couplings avoid the need for welding or other joint types. Instead, they use three components: 1) pipe with grooved ends, 2) synthetic rubber gaskets, and 3) c-shaped clamps.
To form a joint, installers butt two pipes with grooves cut in the ends together. A lubricated gasket slips over the pipe ends so that it overlaps the joint. And a c-shaped clamp or housing fits into the grooves of the pipe, compressing and stabilizing the gasket. This video from Victaulic shows how the joints are made:
But as we mentioned, there are two kinds of grooved joints. So, what’s the difference between a rigid and flexible coupling?
From the outside, you can’t look at a grooved coupling and know whether it’s rigid or flexible; they look the same. The difference is on the inside of the joint in the way that the gasket, groove, and clamp fit together. A rigid clamp permits next to no separation, rotation, or angular movement. But a flexible coupling permits some movement and space without compromising the seal or damaging the pipe. NFPA 13 officially describes how much flexibility is allowed:
3.3.83 Flexible Coupling. A listed coupling or fitting that allows axial displacement, rotation, and at least 1 degree of angular movement of the pipe without inducing harm on the pipe. For pipe diameters of 8 in. (200 mm) and larger, the angular movement is permitted to be less than 1 degree but not less than 0.5 degree.
Key to this definition is the term “listed.” A testing laboratory such as UL or FM Global must verify that a flexible grooved fitting meets specific flexibility, seal, and strength requirements before it can be used in a fire sprinkler system.
This diagram from Bentley Communities helps illustrate the physical difference between the two types of joints:
Almost all grooved couplings use rigid joints because rigid, unmoving joints are desired for most situations. But flexible couplings, while less common, do play essential roles in seismic protection for fire sprinkler systems that require an earthquake-resistant design.
Some fire sprinkler systems require design measures to protect them from earthquake damage. In our overview of the principles of seismic protection, we explain the two basic techniques for protecting pipes from damage: adding rigidity and adding flexibility. Rigidity, in the form of seismic bracing, ensures that pipe moves with a building in an earthquake instead of shaking violently and breaking loose.
Flexibility, on the other hand, prevents damage to pipes caused by differential movement. When an earthquake’s powerful p-waves shake a building, the whole structure can move—but not always all at the same time. For example, the ground floor moves first in tall buildings, and the top floors lag behind. This wave-like motion that resembles a slinky is called “story displacement.” And the differential movement it causes in various onsite equipment can snap fire sprinkler pipes.
The solution to this problem is flexibility, which designers can achieve with flexible grooved couplings. The modest ‘give’ allowed by these devices can prevent pipes from being damaged in an earthquake.
NFPA 13 requires grooved flexible couplings for pipes that are 2 ½” or larger (Section 18.2.1) in certain buildings that fall into specific design categories (SDC). And because story displacement significantly affects risers, most of these rules involve risers (18.2.3.1):
Flexible couplings are also required at horizontal tie-ins to the riser (18.2.3.2) and the connection of drop-pipes (18.2.4).
Flexible couplings allow flexibility when two structures move independently. But don’t forget that bracing, which ensures pipe moves with a building, is the other core technique of seismic design. Flexible couplings can work against this objective by reducing rigidity. So, to compensate, NFPA 13 says that flexible couplings should only coincide with structural separations (18.2.2). And where they are used outside the explicit instructions, extra sway braces are needed (18.2.3).
In our previous blogs, you can learn more about the principles of sway bracing and how cable sway braces work.
Flexible couplings can also be used to construct seismic separation assemblies. These pipe assemblies are used where horizontal pipe must cross an engineered gap, called a seismic joint, between two structures.
The “structures” can be two independent buildings or two freestanding wings of the same building. When a pipe crosses a gap like this, NFPA 13 requires seismic separation assemblies (18.3.1) to keep it from breaking when the two structures move during an earthquake.
There are two ways to build a seismic separation assembly (18.3.2). One approach uses flexible pipe arranged in a u-bend. The other involves a zig-zag pattern of flexible grooved elbows. Either way, the assembly should accommodate a wide range of motion in three directions: the complete closing of the gap between the structures, a doubling of the gap, or lateral movement equal to the size of the gap.
You need a stiff joint for the vast majority of sprinkler pipe connections. That’s why most grooved pipe joints use rigid couplings. But sometimes, flexibility is necessary for seismic design, and the extra range of motion provided by flexible couplings can prevent earthquake damage.
Be sure to check your local codes, including whether a building falls within a seismic design category (SDC) that requires special equipment to keep fire protection systems safe. A qualified system designer must make this determination. Regardless of what you need, QRFS can provide:
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