Concrete Pressure Pipe Tapping Systems
Tapping prestressed concrete pressure pipe is a common occurrence in today's public works projects. Price Brothers Company Field Service Representatives are fully equipped to provide the technical expertise, material, and installation services to make service taps up to 48 inches in diameter (and larger under certain circumstances) on any type of pressure pipe. In most cases, this work can be done under pressure without interrupting service to customers. Price Brothers Company stocks tapping saddles and valves for 3/4-inch to 2-inch threaded connections and most common flanged tapping connections. Price Brothers can also fabricate tapping saddles for all sizes and types of pipe and all sizes of taps. These readily available tapping saddle assemblies provide a secure and economical means of making large diameter taps.
Threaded Pressure Taps
Tapping saddle assemblies can be supplied which have been drilled and threaded to match AWWA standard threads or standard iron pipe threads (NPT) as needed. Tapping machines for installing these taps should be equipped with high-speed, spiral flute, carbide-tipped drill bits. There are two types of small threaded tapping saddle assemblies that are used, strap-type and strapless.
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Strap Type Taps
One style of small threaded tap for making service connections ranging from 3/4 inch to 2 inches in diameter is the strap type saddle. These strap type assemblies are carried in stock for lined cylinder pipe and can be quickly fabricated for all sizes of concrete pressure pipe. The tap consists of a saddle with bolt-on steel straps, rubber gaskets, a gland, and a corporation stop.
Making a threaded tap on pressurized concrete pipe is relatively easy. The procedure involves chipping away the mortar coating on the pipe's exterior where the tap will be made, installing the saddle before cutting and removing the exposed prestressing wire, attaching the gland and corporation stop, testing the gland seal, and then tapping the steel cylinder and concrete core.
After the tap is completed, the whole tapping saddle assembly is encased in a concrete or mortar mix for corrosion protection. The taps can be easily encased using a cloth grout band around the exterior of the pipe, encircling the straps and then filling the grout band with grout.
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After the tap is installed, all metal parts must be encased in a 1:3 concrete or mortar mix with a minimum cover of 1 inch.
Strapless Taps
The second type of small tap, identified as the wire anchor or "strapless" tap, can be used for taps ranging from 3/4 inch through 1-1/4 inches in diameter on lined cylinder pipe diameters from 16 through 36 inches. These taps are anchored to the prestressing wires by split studs which eliminate the need for bands and excavation all around the pipe.
This type of tap requires the exterior mortar coating on the concrete pressure pipe to be chipped away in the area where the tap is to be made. Split studs are then attached to the prestressing wire. The saddle is tightened down on the studs, and the prestressing wire is anchored prior to cutting and removing it from the area to be tapped.
The gasket and gland are then mounted on the pipe, the corporation stop is attached, and the tap is made. The whole assembly is covered with a concrete or mortar mix for corrosion protection once the tap has been completed.
Use this method for 3/4-inch
to 1-1/4 inch connections on 16-inch
through 36-inch lined cylinder pipe.
After the tap is installed, all metal parts must be encased in a 1:3 concrete
or mortar mix with a minimum cover of 1 inch.
Flanged Pressure Taps
Flanged tapping saddle assemblies with outlets 3 inches in diameter and larger can be supplied, which include the tapping saddle, steel bands, rubber gaskets, and a separate flanged tapping gland. Carbide-tipped shell cutters and pilot drills, and power-operated tapping machines are recommended for making large taps in concrete pressure pipe. Tapping gate valves for large diameter taps are available from most valve manufacturers and can be obtained through Price Brothers Company. When specifying tapping valves larger than 12 inches, it is important to compare the inside port diameter of the valve with the outside diameter of the intended tapping machine shell cutter.
As is the case with smaller taps, the flanged outlet tap requires chipping away the mortar coating in the area in which the tap is to be made, attaching the tapping saddle, then cutting the prestressing wires, installing the gland and tapping valve, testing the gland seal, bolting on the tapping machine, making sure it is properly supported, and then proceeding with the tap. When the tap is completed and the valve closed, the entire tap assembly should be encased in concrete for corrosion protection.
 On lined cylinder pipe, flanged outlet taps can be made for branch lines which have diameters as large as one size smaller than the diameter of the concrete pressure pipe to be tapped. Taps on embedded cylinder pipe should be restricted to diameters two sizes smaller than the pipe to be tapped. Price Brothers Company does not advocate the use of taps that are accomplished by welding the gland to the steel cylinder.
After the tap is installed, all metal parts must be encased in a 1:3 concrete
or mortar mix with a minimum cover of 1 inch.
For further information on tapping concrete pressure pipe, consult the AWWA M9 Manual. For specific concerns, recommendations, or assistance that you may require to make your tap a successful one, contact Price Brothers Company.
Jump to another section of the manual:
Standard Pipe | Joints | Bevels & Deflections | Outlet Pipe | Elbows
Tees, Wyes & Crosses | Reducers | Adapters
Tapping | Suggested Specifications | Field Service Repair
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