DataSheets Tips

7/27/2019 DataSheets Tips

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For most engineering-procure-ment-construction (EPC) proj-

ects in the chemical process in-dustries (CPI), the data sheets

developed at the beginning of the pro-cess provide the shopping lists thatguide the procurement group on thepurchase of equipment, system pack-ages, instruments and more. Datasheets should function as the centraldocument, into which all final resultof design or specification calculationswill be transferred, to commence theprocurement process.

During the operation of the facility,

well-crafted data sheets will be usedas key reference documents. They canalso provide crucial information dur-ing debottleneck and retrofitting proj-ects on existing plants.

There are usually five disciplinesthat deal with tangible goods (suchas equipment or instruments) in anEPC project. They are the mechanicalgroup, the instrumentation-and-con-trol (I&C) group, the piping group, theelectrical group and the civil group.

Another group the process group

does not typically manage the pur-chasing of items. Rather, the processgroup is principally responsible fordesigns and specifications. They dontown any tangible goods (such asequipment or instruments) and thus,they usually dont manage the pro-curement process.

Each of these groups is generally theowner and buyer of certain itemsrequired by the project or facility. Forexample, the mechanical group is theowner and buyer (working throughthe procurement group) of equipmentcomponents. The I&C group is re-sponsible for design and purchase of

the instruments and control software.The electrical group is responsible fordesigning and buying electrical itemssuch as electric motors. When it comesto piping, the piping group does not

necessarily design the piping itemsper se, but this group is responsiblefor buying standard and off-the-shelfpiping components. Typically, the pip-ing group provides a list of availablepipes, valves and fittings, and the de-sign engineer selects the most suitableitems from those piping-specificationdocument.

For the piping items that are listedand specified in the piping-specifica-tion documents, there is no need toprepare separate data sheets for them.

However, there may be some items thatwill be installed on or in the piping butthat are not listed in the piping-speci-fication documents. These include spe-cialty items, such as strainers, injec-tion quills and more. These are itemsthat are not typically standardized inthe piping-specification document andthus must be described in a data sheet.

As a result, the data sheet should beprovided for all specialty items.

As noted, the process group is theonly group that is not the owner (and

buyer) of any tangible items. How-ever, this group is often the first groupthat does the preliminary design ofitems required by almost all otherdisciplines, the process group is oftenresponsible to start preparing datasheets for equipment components andsystems, instruments, specialty itemsand even process-related civil items.

However, not all the data sheetsstart with the process group. For ex-ample, some purely mechanical items(such as gear boxes) might start withmechanical group.

Usually the data sheet for inline ele-ments, such as sensors, control valves

and switching valves, is prepared bythe process group first. Then, the I&Cgroup completes the data sheet byadding information that is required tomake the purchase.

However, the data sheet for the of-fline elements of control systems suchas transmitters and indicators can beinitiated by the I&C group, by usingprocess data that was already pro-

vided by the process group for the rel-evant primary elements. For example,an I&C engineer can prepare the data

sheet for a flow transmitter based onthe information that was provided onthe flowmeter data sheet.

Equipment data sheetsThe amount of information on anygiven data sheet can vary greatlyfrom a few sentences on informationin a call-out box showing the equip-ment components in P&ID up to infor-mation in the equipment-specificationdocument. The information in thatdatasheet should be more in-depththan the information in the call-outbox but definitely more brief than theinformation in the equipment-specifi-

Feature Report

44 CHEMICAL ENGINEERING WWW.CHE.COM JULY 2013

Engineering Practice

Data sheets should function as the central document

to guide the procurement process

Getting the Most

Out of Data Sheets

Process P&ID

ReviseP&ID

PFD

RevisePFDProcess datasheet

(PDS)

Mechanical

Instrumentationand control

Electrical

Datasheet (DS)

Requistion package

Vendors Proposals

FIGURE 1. This flow chart shows howa given data sheet may work its waythrough the different disciplines. Eventu-ally, completed data sheets will guide thediscussion with vendors, and the datafrom the final revised data sheet will beused to update other key documents,such as the process flow diagram (PFD)and the P&ID.

Mohammad ToghraeiEngrowth Training


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cation document (which may be a fewpages long).

Data sheets can be classified basedon the level of detail that design en-gineers are willing to show on them,according to two types:1. Black box (functional) data sheets2. Conventional (detailed) data sheets

In black box (functional) data sheets,the design engineer basically defines

what the feed is and what the requiredproduct will be. Additional data, suchas the utility consumption table andpossibly assigned footprint area couldbe added to black box data sheets,too. Using this type of data sheet, the

vendor has the flexibility to select anddesign different types of systems thatcould meet the requirements of the cli-ent.

Conventional (detailed) data sheetsare those that include all the detailedinformation that is needed for the

vendor to design the requested equip-ment. These offer less room for vendor/manufacturer creativity.

Data sheet templatesThere are generally two ways to de-

velop data sheets. In the first method,the process group starts with thedata sheet (specifically, a process datasheet, or PDS). This group does thework to create the first version of adata sheet, and then the individualdisciplines amend and revise that

data sheet to add relevant, discipline-specific information. The group thenissues the final data sheet to the en-gineering discipline, which is respon-sible for the procurement activities(through the procurement group). Forexample, in preparing the data sheetfor equipment, the mechanical groupwill issue the final (amended) versionof the data sheet, which could then benamed mechanical data sheet (MDS).

Figure 1 shows a non-inclusiveflow chart of how a given data sheetmay travel through the different dis-ciplines. As shown, the data sheetswill eventually be updated based on

the communication and discussionwith vendors, and the data from thefinal revision of the data sheet mustultimately be used to update other keydocuments, such as the process flowdiagram (PFD) and the P&ID.

In the second method, an estab-lished data sheet can be used as ageneric template, allowing all of theblank cells to be filled out by the dif-

ferent disciplines. The second methodis more suitable for cases where thecompany is already fully aware of thedetail of the equipment or packagethey plan to buy. In this method, thereis no separate PDS or MDS and no in-terim data sheets.

For standard equipment such aspumps and heat exchangers, a varietyof data sheet templates can be foundin the respective standards. The Tableshows a non-inclusive example of thetypes of data sheet templates that can

be found in the industry standards.For less popular or custom-made

equipment, the primary templatecould be found in different techni-cal books. For instance, Ref. [1] offersa good collection of equipment datasheets. If a package is to be bought,the design engineer should developtailor-made data sheets.

Avoid poor practicesThe process of preparing strong, rel-evant data sheets will be improved by

avoiding the following poor practices:1. Using TBD (to be determined)notations.If the TBD convention is tobe used as a place-holder until finaldetails can be gathered, be sure to fol-low up to make sure the missing infor-mation is provided in suitable time.

2. Using by vendor in places that thedata should really be provided by the

client or engineering company. To bemore specific, all of the boundary in-formation (such as pressure, tempera-ture and so on at the edge or border of

vendors scope of work) should be pro-vided by the engineering company. Forexample, engineering company must

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EQUIPMENT TYPES FOR WHICH STANDARD DATA SHEET TEMPLATESARE AVAILABLE

Equipment Industry standard

Centrifugal pumps API-610, ASME B73.1, B73.2

Controlled volume (PD) pumps API-675

Heat exchangers, S&T API-660

Centrifugal compressors API-617

Steam turbines API-611

Rotary pumps API-676Reciprocating pumps API-674


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Engineering Practice

46 CHEMICAL ENGINEERING WWW.CHE.COM JULY 2013

report the required pressure at theedge of the package boundary.

3. Failure to clarify definitions of keyterms. The engineering company and

vendor should clarify the definitions ofcritical terms, such as normal, design,rated, maximum, design and rated ca-pacities. In some companies, ratedand design are two names for thesame concept, and maximum doesntnecessarily mean the design param-eter.

4. Failure to define potential material-

compatibility and corrosion issues.There are two approaches for specify-ing materials of construction for spe-cific equipment components and pack-

ages. Using the strict approach, theengineering company or client wantsto have the equipment with a specific,stated material. In this approach, in-stead of reporting potentially corro-sive materials that the componentsmay be exposed to, the material ofconstruction should be requested di-rectly. For example, if the team wantsto have equipment built from an acid-resistant material in Region two ofNACE 175, reporting the corrosiveagents and their concentrations may

leave the decision open to vendor tointerpret the data and suggest souror non-sour materials. If the designengineers intend to leave the mate-rial-selection decision on the vendor,they need to choose the second option,which reports corrosive or erosive spe-cies with their concentrations.5. Using brand names instead of ge-

neric names for required equipmentand packages. Brand names should beavoided as much as possible to ensurethe fairest, most competitive bids from

all vendors.6. Risking errors by inserting informa-tion or data that should more appro-

priately come from other disciplines.Sometimes the boundaries betweenthe disciplines are not very clear. Insuch cases, the test question shouldbe Am I completely competent to pro-

vide this number or information? Forexample, in pump-related data sheets,specifying the rpm of the impeller isnot generally the responsibility of theprocess group. However, if the pump

will be handling oily water or waterwith fragile, suspended solids, theprocess engineer could have some spe-

cific mechanical requirements, suchas maximum rpm or the clearance ofthe pump. It is better to cover theselimitations in a note within the data

sheet rather than in the main bodyof the data sheet, because processrequirements are not the only cri-teria required to specify the rpm ofthe impeller.7. Putting extra notes in note area. The

use of notes should be avoided unlessit is truly justifiable. Notes typicallyhave several inherent issues. First,they are often overlooked. Second,they introduce the chance of being inconflict with the information in themain body of the data sheet. If one

data sheet has too many notes in thenote area, it suggests that the selecteddata sheet template was not suitablefor the required equipment. The tem-plate should be designed in such a waythat the data are mentioned in themain body of the data sheet, as muchas possible.8. Including too much information.Putting in information that is not re-lated to manufacturing the equipmentcan be confusing for the vendor. Theengineering company should be care-

ful to put in just the most relevantinformation. For example, for a pumpdata sheet, the normal and maximumflowrate must be specified. However,for the pump to work in differentservices and flowrates, the engineer-ing company might choose to put onerepresentative condition (includingflowrate and required head) in thepump data sheet. In such cases, theengineering company (not the vendor)is responsible to verify whether theproposed pump can handle all of the

operating cases properly.In some cases, the manufactur-

ing company may be willing to workclosely to cooperate with the engineer-ing company if competing operatingscenarios are complicated.9. Erratic management of data sheet

revisions. The procedure for revisingthe data sheet during the design andprocurement process should be agreedto by all parties. The procedure couldbe more complicated if there are morethan one data sheet for an equipment

like process data sheet (PDS) and me-chanical data sheet (MDS). All partici-pants should agree on confusing issues

ahead of time. For instance, if an MDSis developed based on a PDS and theprocess group changes a number in adesign, should they go and reflect the

changes directly in the MDS, or do theyneed to start from the PDS? Similarly,if the vendor (with the agreement ofthe client) decided to change a num-ber in the equipment design, should itbe reflected only on MDS, or on bothMDS and PDS. All participants shouldagree on these issues ahead of time.10. Inconsistency with other docu-ments. The information on the datasheet should be consistent with otherdocuments that have similar content,such as P&ID or LDT. For example, a

line-designation table (LDT) whichis basically a list of all pipes in theplant specifies the design tempera-ture and design pressure of the pipes.These parameters on the data sheetshould be matched with the parame-ters on the LDT. However, matchingdoesnt mean the numbers should beidentical. For instance, a designer candecide to put a lower design tempera-ture and pressure (on the instrumentdata sheet) for a sensor in a pipe withhigher design temperature and pres-

sure. This is acceptable as long as theresidual risk of this action is withintolerable range of the client.

Considering the above practicalpoints during the preparation and is-suing the data sheets will minimizethe debate with vendors and decreasethe number of frustrating cost-ad-ders during the project. n

Edited by Suzanne Shelley

Reference

1. James, R.,and W. Roy Penney, James R. Fair,

Chemical Process Equipment: Selection andDesign, 2nd Ed., Gulf Professional Publish-ing, 2009.

Author

Mohammad Toghraei,P.Eng., is an instructor andconsultant with EngrowthTraining (Phone: 403-808-8264; Email: engedu.ca),based in Calgary, Alta. He hasmore than 20 years of experi-ence in the field of industrialwater treatment. His primaryexpertise is in the treatmentof wastewater from oil andpetrochemical complexes. He

holds a B.Sc. in chemical engineering from Is-

fahan University of Technology, and an M.Sc. inenvironmental engineering from Tehran Univer-sity, both in Iran. He is also a member of APEGA(the Assn. of Professional Engineers and Geosci-entists of Alberta).

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DataSheets Tips