||Pre engineered buildings are on the average 30% lighter because of the efficient use of steel. Primary framing members are tapered built up section. With the large depths in areas of higher stress.
||Primary steel members are selected hot rolled “T” sections. Which are, in many segments of the members heavier than what is actually required by design? Members have constant cross section regardless of the varying magnitude of the local stresses along the member length.
|Secondary members are light weight roll formed “Z” or “C” shaped members.
||Secondary members are selected from standard hot rolled sections which are much heavier.
||Quick and efficient: since PEB’s are mainly formed by standard sections and connections design, time is significantly reduced. Basic design based on international design codes are used over and over.
||Each conventional steel structure is designed form scratch with fewer design aids available to the engineer.
|Specialized computer analysis design programs optimize material required. Drafting is also computerized using standard detail that minimize the use of project custom details.
||Substantial engineering and detailing work is required from the very basic is required by the consultant with fewer design aids.
|Design shop detail sketches and erection drawings are supplied free of cost by the manufacturer. Approval drawing is usually prepared within in 2 weeks.
||Extensive amount of consultant time is devoted to the alterations that have to be done.
|PEB designers design and detail PEB buildings almost every day of the year resulting in improving the quality of designs every time they work
||As each project is a new project engineers need more time to develop the designs and details of the unique structure.
||Average 6 to 8 weeks
||Average 20 to 26 weeks
||Simple design, easy to construct and light weight.
||Extensive, heavy foundation required.
||Since the connection of compounds is standard the learning curve of erection for each subsequent project is faster.
||The connections are normally complicated and differ from project to project resulting tin increasing the time for erection of the buildings.
|Periodic free of charge erection is provided at the site by the manufacturer.
||There has to be separate allocation of labour for the purpose of erection.
|ERECTION COST AND TIME
||Both costs and time of erection are accurately known based upon extensive experience with similar buildings.
||Typically, conventional steel buildings are 20% more expensive than PEB in most of the cases, the erection costs and time are not estimated accurately.
|The erection process is faster and much easier with very less requirement for equipment.
||Erection process is slow and extensive field labour is required. Heavy equipment is also needed.
||The low weight flexible frames offer higher resistance to seismic forces.
||Rigid heavy frames do not perform well in seismic zones.
|OVER ALL PRICE
||Price per square meter may be as low as by 30 % than the conventional building.
||Higher price per square meter.
||Outstanding architectural design can be achieved at low cost using standard architectural details and interfaces.
||Special architectural design and features must be developed for each project which often require research and thus resulting in higher cost.
|SOURCING AND COORDINATION
||Building is supplied complete with all accessories including erection for a single “ONE STOP SOURCE”.
||Many sources of supply are there so it becomes difficult to co ordinate and handle the things.
|COST OF CHARGE ORDER
||PEB manufactures usually stock a large amount of that can be flexibly used in many types of PEB projects.
||Substitution of hot rolled sections infrequently rolled by mills is expensive and time consuming.
|Change orders are easily accommodated at all stages of the order fulfillment process. Little or no material is wasted even if a change order is made after fabrication starts.
||Change orders that are made after the dispatch of hot rolled sections result in increasing the time and cost involved in the project.
||Designed to fit the system with standardized and inter changeable parts. Including pre designed flashing and trims. Building accessories are mass produced for economy and are available with the building.
||Every project requires different and special design fro accessories and special sourcing for each item. Flashing and trims must be uniquely designed and fabricated.
||All project records are safely and orderly kept in electronic format which make sit easy for the owner to obtain a copy of his building record at any time.
||It would be difficult to obtain project records after a long period of time. It is required to contact more than one number of parties.
|Future expansion is very easy and simple.
||Future expansion is most tedious and more costly.
|SAFETY AND RESPONSIBILTY
||Single source of responsibility is there because all the job is being done by one supplier.
||Multiple responsibilities can result in question of who is responsible when the components do not fit in properly, insufficient material is supplied or parts fail to perform particularly at the supplier/contractor interface.
||All components have been specified and designed specially to act together as a system for maximum efficiency, precise fir and peak performance in the field.
||Components are custom designed for a specific application on a specific job. Design and detailing errors are possible when assembling the diverse components into unique buildings.
|Experience with similar buildings, in actual field conditions world wide, has resulted in design improvements over time, which allow dependable prediction of performance.
||Each building design is unique, so predication, of how components will perform together is uncertain. Materials which have performed well in some climates may not do well in other conditions.