Design your own Dental Suction System

The careful planning and logical design of the "central dental suction system" will ensure a lifetime of trouble free operation. 
In contrast, a hastily built system can lead to years of regular breakdowns, expensive repairs, costly down-time and general inconvenience for all concerned. 
When suction pipes are fitted at the time of construction it is crucial to get the design correct. 
Changes or modifications at a later stage will either be very expensive or even  impossible.

"Unplanned down-time can be the most costly item when it comes to repairs"

A few simple rules in designing a good suction system:

1. Use a separate suction line for each surgery - from surgery to plant room. 

The main principal here is that if blockages do eventually occur in one of the pipes/hoses, then only one surgery will be affected while repairs are made.
This prevents downtime affecting the whole practice while the offending pipe/hose is cleaned or removed (for cleaning or replacement). 
- don't be tempted to economise by making one common suction line. 
Joins or junctions that are made under floors or in walls will be impossible to access for cleaning.

2. Types of  pipes
You can go for the less complicated version which is simply 25mm diameter PVC pipe.  I prefer the pipe normally used by electrical engineers. It is usually more expensive than plumbers tubing but the main advantage is you can buy long radius bends which will aid in efficient air flow. Plumbing bends tend to be short and sharp which reduce air flow and can be a starting point for blockages.  As with any engineering, (or dentistry!) the more "prevention" we can "build in" the better!

3. Hose in the tube
A more complex, but service friendly arrangement is to provide 40mm or even 50mm PVC pipe to act as a conduit for a  25mm suction hose. The conduit remains for life as a clean canal for a flexible suction hose. This allows for the hoses to removed and completely replaced after a number years. That way it reduces the need for complex cleaning procedures and the whole operation can be carried out in a minimum of time. The chances of gross contamination of the operatory can be eliminated. 

4. Use long curved bends if possible
    this will allow easy insertion (or withdrawl) of the new hoses or replacement hoses. 

5. Use as few bends as possible
    for the same reason

6. Plan the shortest possible routes
    The length of the suction pipes from surgery to plant room should be as short as possible.

 7. Narrow suction pipes  (ie 25mm diam) will have two advantages:

    a) the air speed will be at a maximum - less tendency for pooling of liquids and 
        stagnation which can lead to blockages. 

    b) the smaller volume of air between suction tip and vacuum motor allows for shorter 
        latent time" ie the time it takes for the suction to "build up" to working level at the 
        suction tip. Remember that very long and wide bore suction pipes will cause 
        unacceptable latent times and may allow gurgling noises due to intermittent pick-up 
        of fluids that accumulate in lower  points along the route.

Note:  If  the length of pipes between the surgery and Plant room exceeds 5 metres then a wider bore pipe/hose will have to be considered.  It can be shown that the friction between air and inside walls of the pipe is proportional to the length of the pipe.  Therefore it may be prudent to look up some engineer's tables on lamina air flow to work out the best compromise.

The hose change-over  procedure:

a) The suction hose is detached from the chairside and sealed off.

b) a stong "drawer cord" is attached to this end.

c) The suction hose is detached from the separator in the plant room 
    and sealed.

d) The suction hose is then carefully pulled out of the conduit from the 
     plant room. 

e) The drawer cord is then detached, ready for pulling the new hose 
    through.

f) The old hose can be bundled, tied and disposed of - preferably 
    incinerated.

g) Some lubricant such as talc powder should be introduced into the
     conduit at the plant room end. An alternative to talc is a special 
     lubricant gel which is obtained from the electrical wholesaler.

h) The new hose is fed into the conduit at the plant room end and a helper 
     pulls the drawer cord out at the operatory end.  The new hose is then 
     cut to length.

i) After all remaining suction equipment has been cleaned and re-installed, 
   the new suction hose can be attached to the suction equipment.

8.  Electric cables
     Run two twin-core electric cables alongside each PVC pipe - leaving some excess for 
     connection at each end. This will allow individual control of the suction motor and 
      each manifold valve in the plant room. .....Note: - The manifold valve can also be 
      located near the chairside if neccessary in which case only one pair of control wires 
      will be needed.

9.  Plan ahead
     Plan the number of operatories and the hardware that will be needed for a fully 
     automatic suction system. Make a detailed list of all materials required.

I hope this has been of some help to you and I wish you many years of trouble free dental suction.  It does make life easier!

I would appreciate any questions, comments or contributions - even constructive criticism! 

John K. Flynn

Email Xerostar Holdings