tanks, pumps, compressors, separators, drying systems, and refrigeration systems. This must include the selection of materials of construction and safety systems and the coordination of specifications with instrumentation and electrical requirements.9 9. Determine size and specifications for all safety relief valves and/or rupture disks for process safety relief (including runaway reactions) and relief in case of external fire.
10 10. Prepare valve code specifications for incorporation on item 7 above, or select from existing company standards for the fluids and their operating conditions (see Figures 14.21 and 14.22).
11 11. Select from company insulation standards (or prepare, if necessary) the insulation codes to be applied to each hot or cold pipe or equipment. Note that insulation must be applied in some cases only to prevent operating personnel from contacting the base equipment. Table 14.1 for typical insulation thickness from which code numbers can be established.
12 12. Establish field construction hydraulic test pressures for each process equipment. Sometimes the equipment is blanked or blocked off, and no test pressure is applied in the field, because all pressure equipment must be tested in the fabricators’ or manufacturers’ shop as per American Society of Mechanical Engineers (ASME) Code.
13 13. Prepare drafts of line schedule and/or summary sheets (Figures 14.20a–14.20d), and equipment summary schedules (Figures 14.23–14.28), plus summary schedules for safety relief valves and rupture disks, compressors and other major equipment. Some of the process data sheets and equipment schedules (over 30) are readily available for downloading from the companion website.
14 14. Prepare detailed process and mechanical specifications for developing proposals for purchase by the purchasing department.
15 15. Participate and possibly lead the process hazard reviews (i.e., hazard and operability studies, (HAZOP) (Chapter 24).
Table 14.1 Typical thickness chart—insulation for services 70°F through 1200°F piping, vessels, and equipment 36” diameter and smaller.
| Insulation thickness | |||||
| Pipe size | 1” | 1½” | 2” | 2½” | 3” |
| ≤2½” | 700°F | 1000°F | 1200°F | ||
| ≤3” | 700 | 900 | 1100 | 1200°F | |
| ≤4” | 700 | 900 | 1100 | 1200 | |
| ≤6” | 600 | 800 | 1000 | 1200 | |
| ≤8” | – | 800 | 1000 | 1200 | |
| ≤10” | – | 800 | 1000 | 1200 | |
| ≤12” | – | 800 | 1000 | 1200 | |
| ≤14” | – | 800 | 1000 | 1100 | 1200°F |
| ≤16” | – | 800 | 900 | 1100 | 1200 |
| ≤18” | – | 800 | 900 | 1100 | 1200 |
| ≤20” | – | 800 | 900 | 1100 | 1200 |
| ≤24” | – | 800 | 900 | 1100 | 1200 |
| ≤30” | – | 800 | 900 | 1100 | 1200 |
| ≤36” | – | 800 | 900 | 1000 | 1200 |
Notes: 1. Temperatures in chart are maximum operating temperatures in degrees Fahrenheit for given thickness.
2. All hot insulated piping shall be coded, including piping insulated for personnel protection. Thickness is a function of insulation composition.
The process design engineer actually interprets the process into appropriate hardware (equipment) to accomplish the process requirements. Therefore, the engineer must be interested in and conversant with the layout of the plant; the relationship of equipment for maintenance; the safety relationships of equipment in the plant; the possibilities for fire and/or explosion; the possibilities for external fire on the equipment areas of the plant; the existence of hazardous conditions, including toxic materials and pollution, that could arise; and, in general the overall picture.
The engineer’s ability to recognize the interrelationships
