ASME Y14.24 Drawing Types

My understanding only:-

1. A source control drawing provides engineering data regarding design requirements and limitations of acceptable replacement parts along with a list of approved suppliers of said parts. You are generally not permitted to source the parts from an unlisted supplier.

2. A Vendor item control drawing provides information relating to the listed suppliers delineating the limits to which replacement parts may vary from the original specifications. It generally keeps control of the paper trail.

3. A procurement control drawing tells you the performance requirements of parts to be acquired including dimensioning and other information critical to future replacement components.

It wasn't unusual to receive number 3 as a specification containing sufficient information to make 1 and 2 redundant, and it was often not a drawing at all but a comprehensive list of notes where the preferred suppliers provided applicable drawings of the specified parts. A paper trail always had to be provided as per #2 to show any deviations from the original specifications and reasons for same. We normally also had a layout or arrangement drawing for obvious reasons.

Thanks for the reply.

Let me pick two examples and see if we are on the same page with them.

ITEM #1: Some sort of a rack mounted Ethernet managed switch or firewall. Setup files, security updates and maintenance of security patches are such an expensive burden that item #1 is essentially a "sole source" item until a few years downstream when its "end of life" makes it necessary to engineer in another "sole source" item.

ITEM #2: The #10-32 screws needed to mount item #1 in the rack.

Both item #1 and item #2 could have procurement control drawings. During development of a large system a procurement control drawing might be very useful. To catch up on documentation of an existing system then procurement control drawings might not be very useful.

It makes sense that a purchasing office should be able to select from the open market any item #2 screw that meet the industry or military specifications on a drawing. That seems to fit best with "Vendor Item Control Drawing".

Countless complex technical details related to item #1 are important and beyond the scope of a purchasing office. In addition, activities such as imposing security patch responsibilities upon other departments are dependent upon current management decisions and therefore are out of scope for a procurement office drawing. Thus, numerous technical details and a specific list of source(s) for item #1 would be listed on a "Source Control Drawing". Procurement could only procure from listed sources. A combined engineering and management effort would be required to update the Source Control Drawing before an additional source could be used.

SUMMARY:

• Procurement Control Drawing - might decide to only do them during a development cycle unless a contract requires them.
• Source Control Drawing - Purchasing must purchase from the listed manufacturer and part number "sources".
• Vendor Item Control Drawing - Purchasing may purchase from any approved vendor offering items that meet the industry, military or other specifications listed on the drawing.

Does this seem correct?

That's pretty much it in my experience.

In your example, I suspect that when it came time to replace that particular item 1., technology would have moved so far that a complete re-engineer was likely, this would probably then require a rethink for item 2. and possibly the rack as well

I agree with Ronsetto that you do need to be careful of quality particularly where critical issues such as your item 1. are concerned.

Where this becomes a problem is where mundane parts such as item 2. are required to be purchased from listed suppliers who then have free rein to charge what they like for them.

In the design stage we normally specified what we required as a minimum but left it to stores to fill in the details which they often did with gusto and, I have always suspected, not a few kickbacks.

We had numerous battles with bureaucracy over this issue - one that comes to mind was a specified service part that had a 14 digit alphanumeric code and a price tag of several hundred dollars. On close examination it became clear that the item was a pair of needle nose pliers essentially identical to what could be purchased at any hardware store for less than 20 dollars and which any service tech. would already have in their kit.

It was, and probably still is, a common practice of hiding mundane items behind long and convoluted part numbers and high price tags, you often had to dig deep to find what the bit really was.

We regularly argued that non critical equipment such as those pliers should be put to open tender - we lost every time.

Thanks for the replies.

No one involved is currently 100% clear on this. There is a requirement we be ASME 14.24 compliant but ........................

I have been out of the engineering document phase for many years now that I am retired. It would appear to me that the proliferation of materials from offshore has something to do with the complicated procurement process. Procurement agencies have to be very careful as to what is procured as quality varies across the board. Procuring a faulty component that leads to a costly failure can have dire consequences. They just can't be too careful these days.

That is bureaucratic insanity at its absolute stinking worst. Several people should get their asses fired, preferably with a blowtorch.

For ASME to create a "standard" that no one seems to understand is pretty sad. With most of the other ASME documents you can at least see "standard format" as a goal. It may seem helpful or harmful to a good engineering department but at least a goal can be seen. Significant parts of the standard Y14.24 look like some strong willed people got together, had a big fight, failed to resolve issues, cashed their checks and went home.

None of this crap belongs on drawings in the first place. That is a bonehead category error. One unified specification document, yes, but not three useless "distinctions." I'm not kidding; heads should roll over this nonsense.

Here's a thought: if the problem is <...can't figure out the difference between these drawing types...> then perhaps there isn't any difference to be <...figure[d] out...>.