Practice Tips #116: All About the Manual Shut-off

What makes your operatory run starts with the manual shut-off valve. Dental delivery systems are all powered by compressed air, some are also connected to municipal water lines. Pipes plumbed throughout the office bring air from the compressor and water to the delivery systems. What makes this all work properly are: plumbing fittings.

In order to connect to your plumbing, the easily overlooked manual shut-off valve is usually used. More properly referred to as an u201cangle stopu201d and commonly referred to as a u201ctoilet valveu201d (connect the water to your toilet). These valves are simple, versatile, and effective.

What Do They Do?

The manual shut-off serves two purposes. Its first function adapts your pipes (usually u00bdu201d copper) to the smaller sizes of lines that your delivery system uses. Second, it allows you to shut the air (or water) to the operatory off, often necessary for maintenance or repair.

To connect to your pipes, the standard manual shut-off has a u00bdu201d female pipe thread inlet at the bottom of the valve. This is a threaded female fitting that attaches to a u00bdu201d i.d. pipe. It simply screws onto your pipe.

The outlet fitting of the manual shut-off is a 3/8u201d brass compression fitting. If uncertain of the size, one measures the diameter of the fitting. Most master valvesu00a0have a 3/8u201d brass compression nipple specifically to attach to the manual shut-off.

As discussed in Practice Tips #5, a compression fitting consists of a nut with a sleeve inside. As the nut tightens down, the sleeve compresses (hence the name) onto the male fitting to hold it in place. Compression fittings are smooth. One does NOT attach to the threads of the compression fitting, those are for the compression nut and sleeve.

Shut-Off Valveu00a0Components

Itu2019s not unusual over time for the compression nut and sleeve to become lost (once used, itu2019s also not normally possible to remove them from the nipple fitting), so we regularly encounter manual shut-offs without the compression nut and sleeve. If your manual shut-off is missing the nut and sleeve, youu2019ll need to purchase a new set to attach anything to your valve.

One often needs to attach to a manual shut-off to add an air powered device (such as a Micro Etcher or lab handpiece) into the lab or sterilization area. A 3/8u201d compression nipple fitting with a tubing connector attaches to the manual shut-off in your lab and also attaches to a standard u00bcu201d o.d. supply tubing. The manual shut-off has a 3/8u201d compression outlet, so you must use a 3/8u201d compression nipple to attach to it. There are a variety of 3/8u201d compression fittings to allow attaching to different sizes of tubing, pipe thread, or other fittings.

Manual shut-offs are used in many places throughout your officeu00a0u2014 under sinks, in the ops, in the lab or sterilization area, and even to connect your toilets. Knowing how to work with these valves will save you both time and money that can be spent elsewhere.