Printer Friendly

Pipe fittings.

Fittings allow the d-i-yer to install pipe in the proper place and end it at the right spot. In both pressure and drainage systems, each kind of pipe requires its own type of fitting. However, there are similarities among all fittings and by understanding the proper application for each, you can save your customer time, material and labor.

The two basic designations for pipe fittings are male and female. These refer to the threading. Male threading is on the outside and threads into the female threading, which is on the inside of the fitting.

Fittings for copper pipe must be soldered, compressed or flared. Plastic fittings for plastic pipe, metal fittings for plastic pipe and fittings for connecting plastic to metal pipe are available in insert, threaded, compression and solvent weldable types.


* Transition Adapters (nipples)--extend a line or provide proper threading at the right location. Nipples come in diameters ranging from 1/8" to 4" to match standard pipe diameters and in lengths from close (nipples that are threaded on both ends to a point where threads almost join in the center) through 24". Normal size increments are even inches. Long nipples or "cut lengths of pipe," which are threaded on both ends are available in about 24" lengths, usually increasing in length by 6" increments (30", 36", 42", etc.).

* Couplings (unions)--connect all standard sizes of pipe. Tight seal with a pipe wrench and pipe joint compound will waterproof connection.

* Elbows--change direction of pipe. Most common are 90[degrees] and 45[degrees] elbows, which have inside threads on both ends. A street elbow has inside thread on one end and outside thread on the other.

* Bushings--inserted inside a coupling to reduce the size of the pipe. With a coupling, a run of pipe can be reduced a size or two; with a series of bushings, any number of reductions can be made.

* Reducers--reduce pipe size. Bushings screw into a coupling while reducers screw directly onto pipe threads. Some reduce pipe only one size; others can reduce several sizes.

* Side Outlet Elbow--have three-way outlets. Can be used as corner pieces for railings or fences. Also used for pipe connections on corner construction.

* Crosses and Tees--available in all sizes and shapes. Most common is straight tee, which has three inside threads of the same size that can be used to run three pipes in a "T" shape. Reducing tee has same shape, but two straight ends of the "T" are reduced one size or more.

* Four-Way Tee (Side Outlet)--similar to the side outlet elbow except side outlet runs through the elbow with an opening of the same size on each end. Straight cross has four outlets for pipe of the same size. Side outlet cross has an opening on the side for a fifth pipe of the same size.


* Return Bends and Y Bends--return bends are made in close, medium and open patterns. The close is a sharper bend than the medium, and the medium is a sharper bend than the open. The Y bend is a straight or reduced outlet, which permits connecting pipe of the same or reduced size to a 45[degrees] angle.

* Cleanouts--remove clogs and clean access to internal pipes.

* Closet flanges--connect toilets to drain and vent systems.

* Flexible fittings--are used in repair or to tie into existing drainage systems.


* Ground Joint Union--three-part fitting that connects any standard size pipe where it may be necessary to disconnect later. Because of the bronze-to-bronze or bronze-to-iron ground joint seat, it can be taken apart and reassembled at the nut with a pipe wrench and no joint compound.

* Floor Flanges--connect pipe to a wall, floor or any flat surface. Flanges are threaded onto pipe and tightened. This provides a flange rim with four screw holes, making it easy to fasten pipe to a flat surface.



Plastic fittings for plastic pipe, metal fittings for plastic pipe and fittings for connecting (transitioning) plastic to metal pipe are available in threaded, insert (compression) and solvent-weldable types.

* Threaded plastic fittings thread exactly like metal fittings; however, special transition fittings should be used to connect plastic to metal pipe in hot and cold water systems to prevent leaks caused by the different expansion rates of plastic and metals.

* Insert (compression) fittings are sometimes used with flexible plastic pipe such as polyethylene or polybutylene. insert fittings are inserted into the pipe and compressed and sealed with an adjustable clamp.

* Solvent-weld fittings have specially formed sockets into which plastic pipe is inserted. Fitting and pipe are bonded by a chemical weld using the solvent or cement compatible with the type of plastic being connected.

Manufacturer's recommendations should be followed in making such joints. When done properly, these joints form a permanent weld stronger than the pipe itself.


Instant-connect fittings make it easy for d-i-yers to join tubing or pipe. The homeowner inserts the tubing or pipe into the fitting until it sets, then pulls back to ensure a tight fit. These fittings are tested up to 600 psi and come in a full range of types to connect copper, polybutylene, CPVC and galvanized pipe in 3/8", 1/2" and 5/8" outside diameter. The fittings are easy to use, but some designs do not allow the fitting to be removed for realignment once in position and seated.


Fittings for copper tube can be soldered on at least one end, leaving one or both ends unthreaded. After flux has been applied sparingly (apply lightly--too much flux can cause a corrosive reaction), solder is introduced at the edge of the fitting. It is then drawn, by capillary action, the full depth of the fitting to surround the tube.

The result is a strong, leakproof, bonded joint. The solder is usually applied with a propane torch--a process known as "sweating" fittings.

* Flare and compression fittings are necessary stock items for any store that stocks copper and aluminum tubing. Appliances that use a small amount of water, such as evaporative coolers and humidifiers, use a small-size slip joint tee and saddle tee.

* A slip joint tee is installed by cutting the line and spreading it slightly. The saddle tee clamps onto the line and a hole is drilled in the pipe through the side opening.

* A commonly used fitting in installing dishwashers is the three-way compression step. This fitting, installed on the hot or cold sink supply line, will cut the flow of water to both appliances at the same time.


Solder is used to "sweat" copper fittings; it forms a bonded joint between fitting and pipe. Solders used in the soldering of potable (drinking) water piping must be lead-free.

Flux (liquid or paste) helps keep copper clean during heating and helps solder wet the copper surface. Flux is a necessary add-on sale for anyone buying sweat fittings; so is a small flux brush to apply the flux as well as sandcloth to clean pipe and fittings.

Some fluxes are corrosive and can be irritating, so advise customers to use adequate ventilation and avoid contact with skin and eyes.

Used along with solder, flux prevents oxidation of metals as they are heated. It also chemically cleans the surface of items to be soldered after they have been rubbed clean with sanding cloth. Allowing certain fluxes to puddle inside the tube or fittings may cause flux corrosion. By preventing oxidation, flux allows solder to flow freely, forming a good watertight seal.

Recommend 95-5 tin-antimony solder where frequent, extreme temperature changes and vibration occur. The first number denotes the percentage of tin. The higher the tin content, the more workable the solder. Silver lead-free solder is an alloy of tin, silver, copper and bismuth that is specifically formulated for making joints on copper water lines carrying drinking water. No. 95 tinning flux works well with large-diameter copper pipe; it eliminates pre-tinning of the metal. Instant solder is a one-step solder and flux combination for copper pipe as well as sheet metal and hobby work.



Plumbing fixtures are equipped with a P, J or S trap that is frequently fitted with a clean-out plug on the bottom. The trap bend holds water, which prevents odors from backing up into the home (Check local codes for use of S traps).

* Drum and bottle-type traps for bathtubs or kitchen sinks consist of a cylindrical metal box or settling basin attached to the waste pipe. They are generally provided with a screw-cap cover that can be removed when cleaning is necessary.

* In addition to commonly used 1-1/4" and 1-1/2" P, J and S traps, a retailer who has multiple-unit and commercial accounts may get calls for grease traps, laundry tray and slop-sink traps. These are usually cast iron with clean-out plugs, 2", 2-1/2" and 3" diameters. A grease trap is fitted with baffle plates and placed in horizontal lines.

* In most areas, 1-1/4" chrome-plated brass traps are used in lavatory drains; and satin-finished or nickel-plated brass 1-1/2" traps are standard equipment on residential kitchen sinks (Satin finish is unpolished chrome-plated tubular).

Because these traps are usually manufactured in gauges ranging from light 22-gauge to heavier 17-gauge in extruded tubing and cast brass, you should check local building codes for approved gauges.

* Plastic P and J traps can be used in retrofit as well as new plumbing work with adapters and transitional couplings to connect plastic with other materials.

* Corrugated flexible plastic drain is useful when installing new sinks or vanities with older drain systems. Many times the drain from a new installation will not line up with the old drainpipe. Corrugated, plastic drainpipe allows the d-i-yer to connect misalignments by as much as several inches.


Garbage disposals, dishwashers and special kitchen sinks require tubular brass goods. These include P traps, S traps, J bends, repair traps (with slip joint nuts on both ends), continuous wastes for sinks with double compartments, tailpieces that connect sink strainers to continuous wastes, branch tailpieces that connect dishwasher drains to sink wastes, extensions to slip (straight tube lengths with slip joint nut) and extensions to solder (straight tube with bell end for a sweat extension). These are primarily used in adding disposals to existing sinks. There is demand for 1-1/4" threaded tailpieces that extend lavatory wastes to the correct distance for trap connection.

Fittings for tubular brass consist almost entirely of 45[degrees] ells, 90[degrees] ells, couplings and tees in 1-1/4" and 1-1/2" sizes--all with slip joint nuts and washers. Strap wrenches are recommended for most work with chrome-plated brass, and extra slip joint washers and nuts are a must in the plumbing department because corrosion brings on occasional breakage.

Safety Tips for Plumbing Fittings

** Solvent chemicals for joining PVC and other solvent welded pipe and fittings have fumes, so use plenty of ventilation when using them.

** When sweating a joint, use a flame shield to keep the propane flame from setting fire to surrounding areas, such as wooden floor joists.

** Use safety glasses or goggles, especially when soldering or applying pipe glue to a joint above your head. Also, be sure to wear a hat and gloves.

** Always use lead-free solder on water lines.

Safety Tips for Pipe Joining Supplies

** Do not use too much solder when sweating a joint. Extra solder will drip like water and while it may not cause a fire, it can burn if it drips on you.

** Disconnect the propane cylinder when not in use so the torch is not accidentally turned on and leaks gas.

** Always wear eye protection and sweat joints in a well-ventilated area.

** Never use a torch to remove lead-based paint.

** Never use a propane torch near combustible material.

** Use a fire shield when soldering joints to avoid damaging or catching fire to surrounding areas.
COPYRIGHT 2006 National Retail Hardware Association
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2006 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Plumbing Supplies
Publication:Hardware Retailing
Geographic Code:1USA
Date:Aug 1, 2006
Previous Article:Pipe/tube.
Next Article:Valves.

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters