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X12 511 — Requisition

The 511 carries an internal purchase request (requisition) issued by a requisitioner to a buyer — typical of DoD MILSTRIP and civilian federal procurement programs.

Purpose

The 511 documents an internal material request before issuing an 850 (Purchase Order): NSN (National Stock Number) or internal catalogue code, quantity, required date, fund cite (UIC, ALC), priority (UMMIPS), delivery point. It is the structured EDI form of the DD-1348 or SF-344 paper requisition.

It feeds military procurement systems (DLA EBS, NAVSUP, AFMC) and civilian ones (GSA Advantage). Acknowledged by 997, it downstream triggers an 850 to the supplier once the buyer validates, or an 824 if the request is invalid (obsolete NSN, expired fund cite).

Envelope structure

The 511 travels within the three X12 envelope levels (ISA/IEA, GS/GE with functional group RQ, and ST/SE). Didactic example in release 004010:

x12 example-511.x12 
ISA*00*          *00*          *ZZ*NAVYREQ       *ZZ*DLAEBS        *260514*1100*U*00401*000000511*0*P*>~
GS*RQ*NAVYREQ*DLAEBS*20260514*1100*1*X*004010~
ST*511*0001~
BGN*00*REQ-2026-0042*20260514~
N1*BY*NAVAL STATION NORFOLK*46*UIC-N00060~
N1*ST*USS ACME WAREHOUSE*46*UIC-N00060-WH~
REF*ZZ*ALC-12345-FY26-Q3~
LX*1~
PO1*1*120*EA**NS*5305-00-841-7766~
PID*F****HEXAGON CAP SCREW SS316 M10~
DTM*002*20260530~
REF*PR*02~
LX*2~
PO1*2*40*EA**NS*5305-00-841-7768~
PID*F****HEXAGON NUT SS316 M10~
DTM*002*20260530~
REF*PR*02~
CTT*2~
SE*15*0001~
GE*1*1~
IEA*1*000000511~

Common segments

  • Header — ST, BGN (Beginning Segment), DTM (issue date).
  • Requester / Delivery — N1*BY (requester, UIC), N1*ST (delivery point), REF (ALC, fund cite).
  • Items — repeated PO1 loop with PID (description), DTM*002 (required delivery), REF*PR (MILSTRIP priority).
  • Federal stock — NSN (National Stock Number) in PO107 with qualifier NS.
  • Summary — CTT, SE.

Common pitfalls

  • Obsolete NSN: an NSN now in Standard Stock Mart (SSM) sub-catalog triggers an 824; without a periodic refresh of the internal reference, the requester re-issues the same request endlessly.
  • Fund cite: the UIC + ALC + FY + Quarter chain must be a valid Fund Cite; a closed FY rejects the 511 even if the material is in stock.
  • UMMIPS priority: REF*PR must use the UMMIPS code list (01-15); a non-standard code silently degrades priority to 15 (lowest), creating unexpected delays.

Documentation

The code 511 and the name Requisition are public and listed on x12.org/products/transaction-sets. The complete structure of loops, qualifiers and code lists is distributed by DISA via the proprietary Implementation Guides (TR3). ediverse.io covers only public concepts, the envelope and didactic examples.