There are literally thousands of things that a piper could know about. Piping itself is a world in itself. We were doing manual isometrics. Following things crossed my mind.

[color=#BF00FF]1. You need the discipline and alert mind to mark (always):
a. North
b. Reference PID and Drawing number
c. Line Number and Pipe Class
d. Equipment and Grid references where necessary
e. Dimensions and Elevations.

2. It is always good to draw system isometrics i.e. interconnected lines (network). Checking also gets simpler as the planning becomes clear in one drawing.

3. While taking MTO, it is good to identify assemblies and put the typical MTO in systematic order.

4. And when you are about to sketch, hold your pencil back, stare at the blank sheet and create a mental picture of the isometric. Start only when you are satisfied with your mental picture else you’ll be erasing it thousand times![/color]

People will snicker at manual work but it just gave me a dose of patience. And that in turn coerced me to think how it was possible to create Clash / Interference free layouts in the past without 3D software and efficient manual work. Following things could have been part of action (Kindly correct me where I go wrong)

[color=#FF0000]A. Prepare details for the standard assemblies where required. Examples would be Steam Trap, Sample Connections, Pressure Gauges etc. Reference them wherever you come across.

B. Make standard shorthand listing for Assemblies for MTO. So that typical detail does not need to be repeated endlessly.

C. Always use fixed / agreed elevation in N/S and E/W direction. When there is direction change then change elevation as well. This rule still rules in Pipe Rack

D. After fixing the directional elevations, the trick then would then be not to cross the lines frequently.

E. Prepare details where such intricate crossings could not be avoided.[/color]

End result would be a layout that should not have many clashes / interferences.