ASC Process Systems14062 Balboa Blvd. Sylmar, CA USA www.aschome.com HOW TO USE THE BOEING STANDARD BAC5621 “Temperature Control for Processing of Materials” Quote: \\server-2\d\ASC Items\31342\31342.doc Page #1 The current version is a 2000 version. Sylmar. and most importantly the sales person. and tolerances acceptable for different types of equipment.com What is BAC5621? Boeing’s standard BAC5621 . autoclave/oven design engineer. The most common application for BAC5621 will be ovens and furnaces. The standard is referenced in other Boeing process standards and serves to instruct Boeing plants and sub-contractors on the proper methods. techniques. What does the standard apply to? BAC 5621 applies only for part processes that require BAC5621 compliance. “Temperature Control for Processing Materials” . presses. ASC Process Systems 14062 Balboa Blvd. It is stored in PDF format on ASC’s server under ASC Engineering\Standards folder. CA USA www. Because autoclaves have their own processing standard BAC 49327. is the primary standard and set of rules for temperature control and monitoring of ovens. autoclaves.aschome. Where to find the standard document? ASC has a copy of BAC5621. Who is responsible to understand the standard? BAC 5621 is important to ASC managers. Understanding the requirements of this standard will allow you to protect ASC as well as speak knowledgeably to the customer when discussing temperature control and monitoring requirements. Quote: \\server-2\d\ASC Items\31342\31342. field startup engineers. BAC5621 is rarely required for autoclave processes. and other thermal processing equipment used to manufacturer Boeing parts.doc Page #2 . This provides for +/.10F uniformity of a Class II equipment. system instrumentation (ie.aschome.5F uniformity in our quotation. it is important that we either find out during the quotation phase what class is required.doc Page #3 . For this reason. uniformity survey tolerances. Sylmar. our job becomes much more difficult in that we must meet a much more demanding +/. The startup engineer on the other hand should find out prior to uniformity surveys what class is being applied to the equipment and make sure that it matches what was quoted. In general the customer’s material processing specification will define what class of equipment is required to cure and/or process different composite or metal-bond materials. ASC Process Systems 14062 Balboa Blvd.10F uniformity surveys and will protect ourselves during uniformity surveys. or that we explicitly state the class that we are providing. You can see that depending on the class. Classes range from Class I to Class VI and include information about the temperature range. What class is an ASC autoclave or oven? There is no one answer for that question. if the customer tells us that the autoclave or oven will require Class I operation.5F uniformity versus the +/. and information about chart recorder resolution. Rule #1 – State “Class II” in quotations Unless the customer demands the tighter tolerances and/or specific compliance. we should explicitly state that our equipment will meet the BAC 5621 Class II operation. the uniformity can range widely. I/O) accuracies. maximum control adjustment. CA USA www. Note that even if we state +/.com Class definitions The standard divides equipment into certain classes of operation. we can still state that the equipment will meet BAC 5621 Class II operation. You can see from the chart above. Quote: \\server-2\d\ASC Items\31342\31342. but after we perform secondary calibration it will meet this requirement.10F. The volume is calculated from the actual working volume of the equipment. we can comply with that. Sylmar. Quote: \\server-2\d\ASC Items\31342\31342. Survey requirements The BAC 5621 states a number of requirements for the survey. than do not waste time trying to get +/. Firstly. If customer’s require additional accuracy statement from ASC. here are some important facts that you should know.doc Page #4 .2F. not the entire volume. Ask for the processing specification to verify this. For an oven it would be the internal width x height x depth.5F. CA USA www. Secondly. The quantity of thermocouples will depend on the overall volume of the oven or autoclave. which is fairly tight. In this case our only obligation will be +/. ASC Process Systems 14062 Balboa Blvd. if the quotation states Class II. The standard requires +/. Equipment requirements The most important equipment requirement is the accuracy of instrumentation reading the thermocouples.com Rule #2 – Don’t allow Class I surveys on Class II equipment For you startup engineers. Understand thermocouple quantities The standard specifically identifies the number of thermocouples required during the survey. don’t allow a customer to dictate the more rigid Class I operation if it’s really not required. As you see. The PLC and Opto22 hardware from the factory cannot meet this accuracy. the lowest number is 9 while the highest quantity is 40. you should ask whether the parts processed require Class I operation. Although you are urged to read the entire standard. For an autoclave it would be the working area less the floor.aschome. Quote: \\server-2\d\ASC Items\31342\31342. This would provide connectivity to the customer’s chart recorder or data- logger without the high cost of I/O and programming. Remember this fact when discussing thermocouple quantities with customers. make sure that the certification person sets his data-logger for one reading every 5 minutes. The actual material processing specification should and will define this time period. On an oven the certification personnel will string thermocouples in the oven and pass them through the door. This means that the oven doesn’t specifically have to have the required thermocouples in jack-panel form. ASC Process Systems 14062 Balboa Blvd. They could merely be jacks on the inside that are connected to jacks on the outside. Can you use CPC to perform a survey? No. Use 5 minute data collection interval The standard requires no less than one reading every 5 minutes. Sylmar. the autoclave will most likely require at least 40 thermocouples if it is to meet BAC 5621 uniformity survey requirements. No overshoot allowed The standard does not allow any thermocouple to go over the upper tolerance. Required to use of a simulated load Unlike autoclave certifications using BAC49327. On an autoclave external jacks must be used which parallel our connections in the autoclave. and therefore would require 40 thermocouples in order to perform a compliant survey. This means that a separate chart-recorder or data-logger must be used to monitor the thermocouples. the BAC5621 survey requires a simulated load to be used during the uniformity test. Stabilization period not defined The BAC 5621 does not define the stabilization time required after the highest thermocouple reaches the range. CA USA www. The benefit of this setting is that if a transient deviation (ie. If a customer chooses to perform the test with an empty autoclave/oven. This provides an easy means of connecting the chart recorder to the internal jacks. spike) occurs between intervals. a 10x20 autoclave is 1500 cu. the standard states that the equipment’s instrumentation cannot be used to perform the survey.com Sell additional thermocouples jacks & feed-throughs on larger equipment From above you can see that if we sell a large autoclave.it will pass easier. the logger will not register it. This would in most cases be supplied by the customer or the customer’s representative performing the certification.ft. This adjustment is usually made on the Cal Offset parameter in CPC.aschome. Temperature offset adjustments The standard does allow you to tweak or adjust the instrumentation by a limited amount so that it agrees with the survey chart-recorder readings. Don’t accept a time period without proof that the material specification requires it. don’t argue with him . The additional thermocouples do not actually have to be connected to CPC. so when performing a BAC5621 survey. This means that care should be taken to insure that the air temperature thermocouple is positioned thermally between the part survey thermocouples. For example. This is limited to the adjustment factor on the chart on page 3. It does not help ASC to read more frequently.doc Page #5 .