Have a Plan and Stick to It: Common Compressed Air Drawing Symbols

Mike Tyson once said “everyone has a plan ‘til they get punched in the mouth”. I do believe it’s always important to have a plan, but hopefully your line of work does not involve anyone punching you in the mouth. If this plan is a Piping & Instrumentation Diagram (or P&ID), you’d be best served to follow it to the exact letter (or symbol). Otherwise, you might end up finding some facility or maintenance manager that is of the same mindset as good ol’ Mike.

The Piping & Instrumentation Diagram is a great way to illustrate the layout of your complete system. Different symbols, created by ANSI or ISO, are used to identify the specific items in the diagram and lays out the entire system, installation, and process flow.

Air compressors are the heart of the pneumatic system and have a variety of different types of symbols that can be used based on the style of compressor that you have. Below are some examples of the symbols used to denote an air compressor on a P&ID:

On the left is a generic symbol that can be used for any style of compressor. Moving towards the right we have specific, unique symbols for each: centrifugal, diaphragm, piston, rotary, and screw compressors. As the 4th utility in any industrial environment, air compressors are a critical piece of equipment in the facility. From the compressor there will be a line drawn to denote the distribution system or piping that connects the supply side (air compressors) to the demand side.

On the demand side are a variety of different available symbols for each type of equipment. EXAIR recommends installing filters and regulators at the point-of-use to keep air clean and dry as well as operating at the minimal pressure for compressed air conservation. The symbols below are used for particulate filters, oil removal filters, and pressure regulators:

The symbols on the left denote the EXAIR products on the right: Automatic Drain Filter Separator, Oil Removal Filter, and Pressure Regulator

They’re laid out in this order for a reason which is why it’s important to follow the drawing exactly as shown when installing the equipment. The particulate filter must come before the coalescing filter in the supply line. Since we can experience pressure drop across filters, it makes the most sense to include the pressure regulator AFTER the air exits the particulate and oil removal filters for the most accurate representation of point-of-use line pressure.

Oftentimes, you may encounter a situation where the product you’re looking to use doesn’t have a specified ANSI or ISO symbol. In those cases, what is recommended is to choose any shape you wish and call it out specifically by name. For our Super Air Knives, this would look something like this:

Having a plan is one thing, but it’s important to make sure this plan has been well-thought-out prior to doing any installation work. It’s not that Mike Tyson is going to come around throwing haymakers or biting off ears if you don’t, but you run the risk of wasting quite a bit of time (and money!) by not adhering to the original plan.

If your plan includes using some of EXAIR’s Intelligent Compressed Air Products, give us a call. We have a variety of products ready to ship same-day from stock to help you get the most out of your compressed air system.

Tyler Daniel, CCASS

Application Engineer

E-mail: TylerDaniel@EXAIR.com

Twitter: @EXAIR_TD

Mike Tyson photo courtesy of Abelito Roldan via Flickr Creative Commons License

Common Compressed Air Symbols

When any product / system is designed drawings are made to assist in the production of the designed product. For example if a mechanical part is being machined you may see symbols like these to verify the part is made correctly:

GD&T
GD&T Symbol Examples

Same with an electrical panel, they use symbols like the ones below to note the type of equipment used in a location.

electronic.JPG
Electrical Symbol Examples

 

Then there’s the Piping & Instrumentation Diagram (P&ID)…it depicts an overall view of a system, showing the flow (usually fluid or electricity) through that system’s components, giving the viewer an understanding of the operation, and expected results from said operation.

Some examples of symbols you might find in a compressed air system are:

Compressors:

all-compressor
The one on the left can be used for any air compressor. The others denote specific types of air compressor (from left:) Centrifugal, Diaphragm, Piston, Rotary, and Screw.

 

Air preparation & handling:

filters-and-regulator-symbols-and-pic.jpg
The symbols on the left denote the EXAIR products on the right: Automatic Drain Filter Separator, Oil Removal Filter, and Pressure Regulator

Instrumentation and control:

instrumentation-and-controls1.jpg
The symbols on top denote the EXAIR products below (left to right): Flowmeter, Pressure Gauge, and Solenoid Valve

Occasionally, we’re asked if there are standard ANSI or ISO symbols for any of our  engineered Intelligent Compressed Air Products…and there aren’t.  Perhaps one day they might make the cut, but for now, their standard convention is to choose a shape and call it out by name.  It might look something like this:

sak-pid1
From top left, and then down: Automatic Drain Filter Separator, Oil Removal Filter, Pressure Regulator, and Super Air Knife

If you have questions about any of the quiet EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Jordan Shouse
Application Engineer
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Knowing Your Symbols Is Key To Understanding Your Drawings

There are all kinds of engineering drawings, used for all kinds of purposes:

  • Pipe fitters and millwrights use Plan & Elevation drawings to make sure fluid system flanges, elbows, tees, etc., line up with each other, and don’t run into anything.
  • Exploded view drawings help maintenance folks identify parts, and, when they need replaced, make sure the new ones go in the same way the old ones came out.
  • Fabrication and machining drawings (usually to scale) are used to ensure the part being made is the right size & shape, that mounting holes are in the right place, and that critical surfaces are as flat & smooth as they need to be.
  • Then there’s the Piping & Instrumentation Diagram (P&ID)…it depicts an overall view of a system, showing the flow (usually fluid or electricity) through that system’s components, giving the viewer an understanding of the operation, and expected results from said operation.  It should not be confused with its simpler cousin, the flow chart that is so dreaded by OTE-types (“Other Than Engineer”…you know who you are,) of which these are my favorite examples:

There’s a lot of “life lesson” in these two graphics.

The big difference between a flow chart and a P&ID is the symbols.  In fact, you can find ISO & ANSI standard symbols for many components you’ll find in fluid & electrical P&ID’s.  Some examples of symbols you might find in a compressed air system are:

Compressors:

The one on the left can be used for any air compressor. The others denote specific types of air compressor (from left:) Centrifugal, Diaphragm, Piston, Rotary, and Screw.

Air preparation & handling:

The symbols on the left denote the EXAIR products on the right: Automatic Drain Filter Separator, Oil Removal Filter, and Pressure Regulator

Instrumentation and control:

The symbols on top denote the EXAIR products below (left to right): Flowmeter, Pressure Gauge, and Solenoid Valve

Occasionally, we’re asked if there are standard ANSI or ISO symbols for any of our  engineered Intelligent Compressed Air Products…and there aren’t.  Perhaps one day they might make the cut, but for now, their standard convention is to choose a shape (user preference…you’re the one it’s gotta make sense to) and call it out by name.  It might look something like this:

From top left, and then down: Automatic Drain Filter Separator, Oil Removal Filter, Pressure Regulator, and Super Air Knife

Oh, and if you’ve ever got any questions about your compressed air system that you think looking at a drawing together could help us solve, you can send that drawing to us at techelp@exair.com, and one of us will be happy to help.

Russ Bowman
Application Engineer
EXAIR Corporation
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