04 chapter04 specification_forms

Editor's Notes

• #3: Discuss why the information on a P&ID is not sufficient for everyone who uses the documentation. SCADA – Supervisory Control and Data Acquisition DCS – Distributed Control System PLC – Programmable Logic Controller PAC – Programmable Automation Controller Items that are not specified on P&ID’s are things like: Is the instrument power sourced in the field or is it loop powered? What process fluid is being measured The pressure and temperature requirements for the instrument(s) Electrical classification for the type of area the instrument will be used Flow rate(s) Metallurgical and materials requirements Specification sheets can be and should be in accordance to ANSI/ISA-20-1981 and Technical Reports are in the newer ANSI/ISA-20.00.01-2007 (The textbook references ANSI/ISA-20.00.01-2006; however, 2007 is the latest version as of this writing).
• #4: Discuss how companies modify the specification forms to meet their requirements. When filling out a spec. form, some specific knowledge is required: Process Knowledge Knowledge must be know of how the process works and how it is controlled Process flow rates, temperatures and pressures must be known All process variations should be known Effect of process materials on the wetted parts of instruments must be known Corrosive and hazardous materials must be known and how it will affect equipment Explosion and fire hazards Codes, Specifications and Standard Knowledge Familiarity with national and local standards is required NFPA 70 (NEC) Aware of international standards when required Product Knowledge Vendors and suppliers of devices and equipment must be known Common features of equipment must be know, particularly when having to go out for bid Must understand and know that “hot features” might be “nice to have”; however, not needed for the process. These un-needed features could ellimate vendors from bidding on equipment.
• #5: Have the students download two forms from the LMS or the location you specify. Then have them go through the example in the textbook starting on page 87 – Filling Out Specification Forms, Page 93 – Level Instruments. When they have finished that exercise, have them pick an instrument from the trainers and fill out the forms for that instrument.
• #6: Petroleum and chemical manufacturers are examples of hazardous/flammable materials. “To prevent fires or explosions, equipment use and installation must follow safe practices that are set down in codes.” Some of the codes are: NEC – National Electrical Code CSA – Canadian Standards Association UL – Underwriters Laboratory FM – Factory Mutual CE – Abbreviation of the French phrase “Conformeté Européene” which literally means “European Conformity” (CEmark.com & European.Authorized-Representative.eu, 1996-2015) NEMA – National Electrical Manufacturers Association When using the NEC, be sure to use the code year being used in the state and/or city where the process is located. As an example, even though NEC is the law in all 50-states, different states work from different editions. Pennsylvania is currently using NEC 2008. The latest edition is 2014. The 2017 edition is under review as of this writing (June 17, 2015); however, Pennsylvania is still using 2008 and the legislators recently shot down moving to 2014. That doesn’t mean that their ruling can’t be overturned. This is why you need to become familiar with what standards and codes are being used in the state and city where you’re working. Also be aware of the standard in other countries, especially if you are working for an international company. The next slide is taken from EMEC107 – Instrumenation Safety and graphically shows the electrical Class-Group-Divisions of the NEC 2008.
• #7: Here is another way of looking at the previous chart. So meantime you can work upward on these types of charts to get your designations. What gas or dust are you working with? Present all the time or just abnormally? Classes: Class I – Sufficient quantities of flammable gasses or vapors are present in the air to produce an ignitable mixture and/or explosion. Class II – Sufficient quantities of combustible dusts are present to cause a hazard. (Flour mills, coal pulverizing, cement manufacturing) Class III – Flyings or fibers not normally in suspension in the air are in enough quantity to be hazardous and easily ignited. Groups: Group A – acetylene Group B – butadiene, hydrogen Group C – carbon monoxide, hydrogen sulfide Group D – ammonia, most petroleum products Group E – metal dusts Group F – carbon black Group G - flour
• #8: Briefly discuss Intrinsic Safety. This topic is beyond the scope of this course. The file, ISA-TR12.2-1995 – Intrinsic Safety Assessment Using the Entity Concept can be found in the pdf file “ISA-TR_12-2.pdf”.