ii. Environment condition relative to adjacent properties i.e. proximity to airport
iii. Soil conditions, prevailing wind direction.
iv. Source of water supply and the supply point with respect to the plot.
viii. Geographical factors i.e. wind direction, temperature, rain, frequent thunderstorm and earthquake susceptible areas.
Major Consideration in Plant Layout
|Class of Hazardous||Fire lode (Btu/sq.ft)||Required fire Resistance Rating for Fire Walls(hr)|
|Laws||0 to 100,000||1|
|Moderate||100,000 to 200,000||2|
|Explosion hazard||Minimum clear space |
|E1: Minimum, none or slight; consider negligible E2: Moderate; limited to small area; prompt restoration||None required None required|
|E3: Intermediate; appreciable major equipments||50 ft|
|E4: High; considerable potential or probability; series delays||75 ft|
|E5: Extreme; unpredictable; high potential; disruption||100 ft|
Factors which determine the selection of enclosed buildings are;
a) Nature and frequency of the operator's work- Equipment, which requires frequent maintenance in adverse weather conditions.
b) Climate- Extreme climate conditions may determine that the plant is to be kept in a building.
c) Type of equipment - Expensive equipment and complex machinery should have some degree of weatherproofing.
i) Fire protection/Explosion Protection approval by the local fire authority must be obtained on fire fighting equipment and layout.
Techniques for Layout
Details of Techniques for Layout
Concept of the Plant Layout
2) The block shall be arranged considering the prevalent wind direction such that flammable gases should not be carried by the wind onto a source of ignition.
3) The process unit block shall be centrally located with a straight approach from the main gate.
9) Flares shall be located upwind of the process units so that the inflammable gas from the plant are not carried towards the flares.
10) Truck loading facilities shall be located close to the product movement gate. Rail loading facilities are arranged generally at the periphery of the plant.
|The Present Fact||Alternatives||Selection for Development|
|What is achieved?||why ?||what else |
could be achieved?
|what should be achieved?|
|How it is achieved?||Why that way?||How else could it be achieved?||How should it be achieved?|
|When it is achieved?||Why then?||When else could it be achieved?||When should it be achieved?|
|Where is it achieved?||Why there?||Where else could it be achieved?||Where should it be achieved?|
|Who achieves it?||Why that persion?||Who else could achieve it?||Who should achieve it?|
Stages in the development of the layout
1)The layout begins with the collection and assessment of the flow sheet ( which must show material of construction, size of pipe work and suggested elevation ), equipment data sheets, result of site survey (incorporating relevant data on site boundaries, topography, soil structure, weather conditions, utility terminals and site access points).
Critical examination is used to question the elevation layout assumptions made in the flow sheet. This method enables the objectives and constraints to be defined. Techniques of correlation and compatibility are used to sort and list the various alternatives.
2) The cost of each elevation alternation is examined for differences only e.g. in the number of plant items needed to achieve the objectives in the material transfer costs such as piping elevation, power consumption.
Simple elevation drawings are prepared for the alter natives showing heights and relative positions only of plant items only, No structure or floor levels are added yet as these may depend on plan layout.
3)Plant items and buildings are laid out in the plan ensuring that all layout constrains (e.g. relating to operation, maintenance, safety costing environment and expansion ) are applied A similar costing made of each plan layout is made
Critical examination is used to question the plan layout assumptions made in the defined Once the constraints are defined Techniques of correlation and compatibility are again used to sort and list the various alternatives. Layout analogous such as cut outs help in the visualization of the layout and in the examination of plot size and external constraints.
4) The selected plan and elevation layout are now combine to determine the possible positions of supporting and access structures, and to study the civil requirements. These may force the relaxation of earlier constraints.
The layout alternative is presented by block models. This stage will help people to visualise the non-quantifiable and safety aspects.
5) Final alternatires are again costed for differences and a selection is made.
The final layout is drawn (options may still be left open for detailed study)
6) Preparation of piping models now commences. These are further used to optimize pipe work .A check should be made that all constraints are obeyed particularly those for operation.
Piping models are now prepared.