PLANT LAYOUT CRITERIA AND PHILOSOPHY
LAY-DOWN AREAA Lay-down area is a construction term, which refers to a portion of the site, set aside for temporary storage of equipment.
Contrary to popular misconception that a lay-down area is a portion meant for maintenance purposes, a lay-down area is in actual fact, a hard concrete filled area set aside for temporary storage of equipment.
PLANT LAYOUT PHILOSOPHY
So many criteria are considered when determining the requisite and appropriate spacing between equipment on site.
These criteria are usually based on the classification of such equipment within the facility.
Equipment are usually classified into two. They are:-
1. Process Equipment
2. Utility Equipment
Process Equipment are equipment that are directly involved in the handling of the process fluids (crude or gas). They consists of equipment that perform some of the following functions:-
a. Separation
b. Cooling/Refrigeration
c. Heating
d. Fluid transfer (pumps) etc
Some example of Process equipment includes:-
i. Heat Medium Skid ix. Chillers
ii. Surge Vessel x. Booster Compressors
iii. Slug Catcher xi. Pumps etc
iv. Inlet Separators
vii. Distillation Columns
viii. Flare Knock-out drums
Utility Equipment or packages on the other hand are those that are not directly involved in the handling of the process fluid. They however provide support for the smoooth running of the process packages. They consists of equipment that perform the following functions:-
a. Power Supply
b. Drainage (closed and open)
c. Water Supply
d. Fuel Supply etc
Some examples of Utility packages includes:-
i. Gas Generator
ii. Diesel Storage Tanks
iii. Open Drain System
iv. Closed Drain System
v. Supply Water Tank etc
Plant layout is a crucial factor in the economics and safety of a process plant. Some of the basic factors that engineers consider while determining the requisite spacing between process and utility equipment includes:-
1. Process flow Principle
2. Hazards Assessment - Classification, Ranking and Ratings
3. Containment of Accidents
4. Limitation of Exposure
5. Escape
6. Efficiency and safety in Operation
7. Efficiency ans safety in Maintenance
8. Fire fighting Access & Fire Protection
9. Access for Emergency
10. Security
11. Ventilation
Plant layout can have a large impact on plant economics. Additional space tends to increase safety, but is expensive in terms of land and also in additional pipework and operating costs.
Space therefore needs to be provided where necessary for safety concerns, and not wasted.
HAZARDOUS AREA CLASSIFICATION
When an Electrical Equipment is used in, around or near an atmosphere that has flammable gases or vapors, flammable liquids, combustible dusts, ignitable fibers, there is always a possibility or risk that a fire or explosion might occur.
