Process Diagrams

Question 1

What are process diagrams

Answer 1

Engineered drawings which outline the layout and operation of a process unit or system

Question 2

Block diagrams

Answer 2

Use blocks and flow arrows, shows the “big picture”

Question 3

Process flow diagrams

Answer 3

Shows only major equipment. A limited number of symbols used. Doesn’t show piping/instrument/equipment details

Question 4

P&ids

Answer 4

All major equipment. All safety devices, instrumentation are shown. Needs to be kept up to date. Isn’t shown to scale.

Question 5

Legend

Answer 5

Explains the meaning of each symbol used in that particular set of drawings

Question 6

Critical icons shown on diagrams

Answer 6

H2s area
Safety shower/eyebath
Alarm point
Double hearing protection
Windsocks
Corrosive toxic
Assembly point
Emergency plant/phone
Fire hydrant/manifold

Question 7

Purpose of a P&Id

Answer 7

Are drawn to show you the exact equipment in the plant in complete detail

Question 8

A p&id is not

Answer 8

A piping isometric
Scale drawing
An equipment fabrication diagram
A control logic diagram

Question 9

Safety critical devices

Answer 9

Scd’s normally designated with a double circle

Question 10

Safety critical instruments

Answer 10

Sci is a double circle

If shared within a dcs system, the figure may be a double square