Piping Design Training Course

This is tutorial on Piping Design Training Course is posted with an only intension to help the newbie’s to learn “How to develop piping arrangements”, in fact it is a continuation of the article “How to Design piping system”. However it is assumed that the readers are trained with basic techniques of engineering drafting and Computer Aided Designing’s (AutoCAD).

The relative arrangement of the various equipment and machinery laid in the particular unit or an Area or a site is indicated. It should meet the following requirements:

· Process constraints like minimum elevations, distances, slopes, etc.

· Operational accessibility.

· Maintenance feasibility like monorail, fork-lift or a mobile crane approach, working area, etc.

· Ease of erection.

· Industrial safety.

· Statutory regulations e.g. Petroleum Act/ Gas Cylinder Rules, Static & Mobile Pressure Vessel Rules and Factory Inspectorate Rules.

· Aesthetics (Outward appearance)

· Economy, e.g. shortest piping, smaller floor space, etc.

The scale can be 1:50 on any size of sheet, depending upon the area coverage. As far as possible a nearby road/pipe rack should be shown to make the approach or obstructions clear. If most of the equipment are of large size then scale can be reduced to 1:100, 1:200 or 1:250 e.g. in case of big tank farms, ammonia storage tanks, etc.

Equipment layouts are designed subjected to Process flow Diagrams (PFD) and the list of equipments as compelled by the process requirement. Piping designer shall tentatively locate the equipments simultaneously executing the process requirements. He should maintain a sophisticated sequence of nozzle projections, piping and its components and a uniform distance between the equipments, also keeping structural concrete’s, beams, pipe racks electrical cable trays etc. into consideration.

Initially all equipments are place at the ground elevation but are subjected to change as per the process requirements or respective progress in the project. Equipment layout shall be further proceeded with Inter-Disciplinary check for a relative check of equipment locations and elevations. Formerly when these equipment locations are finalized all major piping i.e.; bigger sized piping’s and critical process lines are routed or placed on the racks in the drawing.

Designing is then promoted with finalization of number and elevation of floors. No sooner the preliminary designing of piping arrangements are initiated wherein each floor is designated in separate sectional views.

For proceeding to preliminary arrangement plans information is collected from various groups, as follows

Process:

· Type of building/structure

· Surface protection requirement.

· Size and type of moving equipment.

· Approach & operating space requirements.

· Type of Hazardous and Safety requirements

Instrumentation:

· Space requirement for instrument cables.

· Space & location requirements for Analyzer cabinets/rooms, etc.

Electrical:

· Space requirement for cable racks & trenches.

· Space for local Push Button Boards

Civil:

· Factory Act requirements.

· Economic consideration with regard to type of structure, column spacing & tie beam, etc. meeting process requirements.

· Size and depth of Building Column Footings

· Size and slope of Floor Drains

Erection:

· Erection requirements such as bolted joints in the structure.

· Erection openings in floors.

· Openings in walls or door sizes

· Extra space for derrick/crane, etc.

Client: Preference for type of structure, maintenance facilities, like cranes, monorails, operational amenities like office, toilet block, change room, lunch room aesthetical preferences, etc. Details are received from all the above groups and the client and copies of Unit Plot Plans including all revisions are distributed to all of them. It is advisable that all proposals be discussed during conceptual stage itself with all groups so as to avoid major revisions at a later date.

Licensor: Usually preliminary arrangement plans are furnished by the licensor (usually on 1:100 scale) and our work is limited to update the same incorporating comments of various groups and exact shape and dimensions of the equipment as and when received.

Following may be noted with regards to contents of the Unit Plot Plans:

· North direction should be shown.

· Each Unit Plan to have a key plan of overall G.A. highlighting the area covered by that Unit Plot Plan.

· All the equipment items should be located by co-ordinates of centre lines or dimensions from a column centre line. Orientation of equipment should be given by locating one big size nozzle usually manhole in plan and elevation. Only elevations should be given. No vertical dimension lines will be added. All elevations should be with respect to +0.00 meters and should be finished elevations.

· Pipe racks, cable racks, attached to the building will be shown. It is preferable to show also the surrounding roads wherever possible.

· Each floor level shall be shown separately.

· Intermediate platforms shall be shown.

· Sufficient sectional views will be drawn. It is better to cover area between two column grids (e.g. one bay) in one sectional view in order to maintain clarity. Requirement of minimum clear, height, bottom elevation of monorails and elevation of top of brackets for travelling cranes should clearly be marked in sectional views.

· Critical lines requiring shortest route or minimum slope from process point of view and lines of sizes >500 mm, from interference and flexibility point of view should be included in the arrangement plan.

· Add pipe rack, cable tray loads for pipe rack plot plans.

· Show hand railings, curbing, etc.

· Mark various floor protection areas.

· Show coverage of roof wherever required.

· Show major openings in floors.

· Show major trenches, sumps and pits.

In absence of any other data agreed, following may be used for developing Unit Plot Plans:

· Minimum clear distance around every equipment : 600 mm

· Minimum clear distance between two equipment : 600 mm

· Distance of equipment from any wall : 600 mm

· Minimum clear headroom below & above any: 2.2 m platform.

· Minimum clear height with R.C.C .Roof : 3.75 m

· Minimum height for bottom of truss tie with : 5.00 m

· Asbestos cement sheets roofing.

· Height of vertical cladding from finished floor level : 3.0 m

· Provide minimum two staircases, if the plant is hazardous i.e. fire hazards. Number of Persons normally working above the ground floor level exceeds 20. Fire escape staircase should lead to ground level outside the building and should be accessible within 25 Mts. (maximum) from any point within the Unit.

· Minimum foundation height for equipment located: 200 mm on the ground from highest finished floor level.

· Highest finished floor level for a Unit/Building: 150 to 200 mm above the surrounding road levels.

· Kerb for openings : 150mm high