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DraftVerify Standards Library · F-36

NA Draft System Failure Modes Guide

Version 1.0 · Publication Date: 2025-01-01 · Status: Active
© 2025 DraftVerify™ Standards Initiative. All rights reserved.

F-36 defines the failure modes, symptoms, root causes, and corrective actions associated with non-alcoholic (NA) draft systems.
Because NA draft requires strict separation and identity preservation, system failures can cause mis-serve, contamination, or integrity loss.

This guide supports breweries, distributors, and venues in identifying issues early and responding with precision.

1. Purpose of This Guide

This document provides:

  • A taxonomy of NA draft failure modes
  • Visual and operational symptoms for detection
  • Root-cause patterns
  • Immediate and long-term corrective actions
  • Preventive maintenance expectations
  • Links to other DraftVerify Standards

Failure mode awareness is critical to consumer safety, identity protection, and regulatory compliance.

2. Scope

This guide covers failures involving:

  • Kegs
  • Couplers & Coupler Tags
  • Beer lines
  • Taps / faucets
  • Gas systems
  • Cold storage
  • Identity workflow
  • Cleaning & service operations

Applies to:

  • Breweries
  • Distributors
  • Venues
  • Draft technicians
  • Auditors

3. Failure Mode Categories

Failure modes are grouped into six major categories:

  1. Identity Failures (highest risk)
  2. Contamination Failures
  3. Mechanical Failures
  4. Gas & Pressure Failures
  5. Workflow Failures
  6. Cleaning & Maintenance Failures

Each category includes examples, symptoms, root causes, and corrective actions.

4. Identity Failure Modes (Critical)

Identity failures directly threaten NA integrity.

4.1 Wrong Keg Tapped

Symptoms:

  • Product taste mismatch
  • Verification scan not matching menu
  • Staff confusion during switching

Root Causes:

  • Incorrect keg movement
  • Failure to scan (F-29 requirement)
  • Cooler disorganization

Corrective Actions:

  • Stop service; quarantine keg
  • Verification scan of all nearby kegs
  • Review switching workflow
  • Update cooler map (F-19 / F-25)

4.2 Coupler Tag Missing or Damaged

Symptoms:

  • Tag not found at spear
  • Zip tie cut or loose
  • “Not Active / Unknown” on scan

Root Causes:

  • Mishandling
  • Tag tampering
  • Wrong coupler tag used

Corrective Actions:

  • Quarantine keg
  • Notify distributor/brewery
  • Review identity chain logs (F-28 / F-31)

4.3 Identity Mismatch in Verification Scan

Symptoms:

  • Wrong brewery, product, or DTI
  • Tag shows previous batch
  • Registry inconsistency

Root Causes:

  • Wrong tag activation (F-13 failure)
  • Distributor error (F-15)

Corrective Actions:

  • Quarantine keg
  • Audit activation records
  • Correct registry entry (if safe to do so)

5. Contamination Failure Modes

5.1 Alcohol Contamination in NA Line (Critical)

Symptoms:

  • Alcoholic aroma or flavor
  • Customer reports “this tastes like beer”
  • ABV detected in testing

Root Causes:

  • Line previously used for alcoholic beer
  • Incorrect cleaning chemical
  • Shared tower with cross-flow (F-25 issue)

Corrective Actions:

  • Immediate shutdown
  • Full system flush
  • Incident Report (F-22 / F-35)

5.2 Residual Cleaning Chemical

Symptoms:

  • Chemical smell
  • Harsh taste
  • Tingling sensation

Root Causes:

  • Incomplete rinsing
  • Wrong chemical dilution

Corrective Actions:

  • Shut tap
  • Flush line thoroughly
  • Retrain staff

6. Mechanical Failure Modes

6.1 Faulty Coupler Seal

Symptoms:

  • Leaks at the spear
  • Gas bubbling in line
  • Foamy pour

Root Causes:

  • Worn O-rings
  • Poor connection
  • Bent coupler handle

Corrective Actions:

  • Replace seal
  • Test coupler alignment

6.2 Keg Pressure Loss

Symptoms:

  • Flat pour
  • Slow pour
  • No flow

Root Causes:

  • Gas leak
  • Empty or warm keg
  • Faulty check valves

Corrective Actions:

  • Check gas system (F-26)
  • Inspect keg seals

7. Gas & Pressure Failure Modes

7.1 Incorrect Gas Mix

Symptoms:

  • Over-carbonation
  • Under-carbonation
  • Foaming

Root Causes:

  • Using CO₂ where mixed gas required
  • Wrong regulator setting

Corrective Actions:

  • Reset regulator
  • Confirm gas type

7.2 Regulator Failure

Symptoms:

  • Pressure drift
  • No consistent flow
  • Safety vent activating

Root Causes:

  • Faulty diaphragm
  • Frozen regulator

Corrective Actions:

  • Replace regulator
  • Inspect gas lines

8. Workflow Failure Modes

8.1 Failure to Scan During Switching

Symptoms:

  • No record of tap change
  • Wrong product served

Root Causes:

  • Staff oversight
  • Training gap (F-23)

Corrective Actions:

  • Review workflow
  • Retrain staff
  • Implement mandatory scan signage

8.2 Cooler Misorganization

Symptoms:

  • Wrong keg pulled
  • Staff confusion

Root Causes:

  • No labeling
  • Mixed alcoholic + NA storage

Corrective Actions:

  • Redesign cooler layout
  • Apply sidewall ID bands (F-6)

9. Cleaning & Maintenance Failure Modes

9.1 Improper Line Cleaning

Symptoms:

  • Off-flavors
  • Film buildup
  • Slow flow

Root Causes:

  • Incomplete cleaning cycles
  • Incorrect procedures

Corrective Actions:

  • Follow manufacturer cleaning protocol
  • Re-clean before service

9.2 Faucet Blockage

Symptoms:

  • Slow pour
  • Dripping
  • “Sticking” faucet

Root Causes:

  • Sugars or proteins buildup
  • Worn washers

Corrective Actions:

  • Disassemble faucet
  • Clean thoroughly

10. Failure Mode Reporting Requirements

All critical and major failures must be documented using:

  • F-22 Incident Response Procedure
  • F-35 Contamination Report
  • F-31 Audit Log Framework

Records must be retained for 10 years.

11. Summary

The NA Draft System Failure Modes Guide:

  • Identifies high-risk failure patterns
  • Enables rapid detection and correction
  • Protects the NA consumer
  • Strengthens the identity chain
  • Reduces mis-serve risk
  • Supports consistent auditability

Awareness and early detection ensure NA draft integrity across all tiers of the supply chain.