21: Design Input Data Issue
Definition/Typical Issues
Was there a problem with the input data for the design? Was there a failure to consider all the appropriate design inputs during the design phase? Were the design criteria so stringent that they could not be met? Were some criteria conflicting? Were requirements out of date?
Was there difficulty in accessing the necessary codes and standards? Was a novel design or concept applied for which there was no applicable prescriptive standard? Do applicable standards lack sufficient detail to be easily interpreted? Was the detail provided insufficient to make interpretation of the standard easy? Is there disagreement with the criteria in an existing standard? Does the current standard fail to address a new technology or material? Was the wrong standard, code, or guideline applied? Was the wrong version referenced?
Were there changes in practice or technology not addressed by an industry standard? Was an emerging technology employed by the company for which no standard existed?
Do two applicable standards contain conflicting requirements? Are there conflicting requirements within a standard?
Did a change in the use of the equipment require the application of a different standard?
Was there a failure to identify customer requirements that should have been incorporated into the design? Was there a failure to communicate customer requirements to appropriate personnel? Were the customer requirements confusing? Were there inconsistencies among the customer requirements standards? Were there inconsistencies among the customer requirements that were used and the actual customer requirements? Were the wrong customer standards applied? Were the customer requirements incorrect?
Was the design incompatible with the system performance objectives or design requirements?
Were the required design data not available at the time the design was finalized?
Examples
Example 1
- During the design of a control system, the timing for a step was set incorrectly. The vendor-supplied information was modified during word processing from 3-4 minutes to 34 minutes. As a result, the system was installed with the timer set to 34 minutes, resulting in too much catalyst being added to the reactor.
Example 2
- A valve failed because the designer used obsolete materials requirements. As a result, products did not meet specifications.
Example 3
- A process upset occurred because one of the flow streams was out of specification. The design input did not indicate all the possible flow rates for the process. The pump was incorrectly sized for the necessary flow requirements.
Example 4
- A flow controller could not adequately control flow during an infrequent operation. The flow requirements for normal, emergency, and infrequent operation covered too wide a range for a controller to operate properly under all of the conditions. As a result of the flow controller failure, a hose was overpressurized and failed.
Example 5
- At the time the cooling system was designed, the heat load from the generator had not been determined. As a result, the cooling system capacity was underdesigned by 10%.
Example 6
- A pressure vessel was being manufactured out of a new exotic composite material. No standard existed to address the use of this material in a pressure vessel.
Example 7
- ASME, API, and ANCE standards all addressed the use of certain steels in an underwater application. However, each standard had some requirements that were contradicted by the other two standards.
Example 8
- A standard required the use of carbon steel in a fire protection system. However, a risk assessment showed that a new fiberglass-reinforced plastic material performed better, but the standard did not allow its use.
Example 9
- A vessel (i.e., a tank) had been used for processing relatively neutral pH fluids. When operation of the tank shifted to use a more acidic material, the inspection criteria were supposed to change based on the new standards that applied. However, no one identified the need for the change.
Example 10
- A recent change was made to a NACE standard that required a different material to be used on a drilling rig. However, no one at the manufacturer noticed that the change affected their rig. As a result, the wrong revision was applied.
Typical Recommendations
- Conduct a feasibility study prior to beginning design to ensure that the criteria can be met.
- Develop an independent review process to help ensure that appropriate standards are used in the design.
- Develop a tracking system to help ensure that current design criteria are used.
- Develop comprehensive system design requirements.
- Develop a design development schedule to ensure that all information will be available when needed.
- Risk analysis should be performed in order to demonstrate equivalency of novel designs with existing standards.
- If the requirements of a standard are unclear, contact standards authorities and request clarification to determine the intent or basis of the standard.
- When a system changes service, a review of existing regulations and standards should be performed to determine whether additional requirements apply.
- If no applicable standard can be identified, request that the appropriate standards organization develop a standard or modify an existing standard to address the situation.
- Review conflicting requirements and comply with the most stringent requirement.
- Contact standards authorities and request a formal ruling in application of the conflicting requirements.
- When the use of equipment changes, review the existing standards to determine whether different requirements apply.
- Ensure that the applicable version/revision of a standard or regulation is applied.
- File documents in a manner that facilitates easy retrieval.
- Eliminate duplicate copies of design information to avoid confusion about which is the "official" version.
- Develop standards for symbols and terminology.
- Implement methods to control access and changes to design information.
- Develop methods for approving changes to design documentation.
- Assign customer service personnel to solicit customer requirements.
- Identify lessons-learned from each design to be used in future designs.
- Define specific methods for customers to communicate with the design group or other company personnel.
- Ensure that appropriate personnel are aware of recommended practices contained in recognized and generally accepted good engineering practices (RAGAGEPs) and apply their requirements.
- Develop a company- or facility-wide standard that summarizes applicable recognized and generally accepted good engineering practices (RAGAGEPs) related to the design, test, and inspection requirements for each type of equipment.
- Actively seek information on new developments in design, test, and inspection requirements.
Cross-References
| Version 10 Element(s) | |
|---|---|
| Node ID | Node Name |
| 16 | Design Input LTA |
| Maritime Element(s) | |
|---|---|
| Node ID | Node Name |
| 23 | Design Input Obsolete |
| 24 | Design Input Incorrect |
| 25 | Necessary Design Input Not Available |