Redundancy for controlled-environmental rooms for safety: we guarantee volumetric uniformity and have never failed a validation

1. 2N VS N+1
REDUNDANCY
FOR CONTROLLED ENVIRONMENTAL ROOMS
DISCUSSION

2. 2N VS N+1 DEFINITIONS
2N
• 100% REDUNDANCY (TWO IDENTICAL
MECHANICAL CONDITIONING
SYSTEMS ABLE TO MAINTAIN
PERFORMANCE SPECIFICATION
INDEPENDENTLY)
• OPTION: CONTROLLER REDUNDANCY
N+1
• PARTIAL REDUNDANCY
• MULTIPLE DEFINITIONS
• SHARED FAN
• ONE EXTRA OF ONE THING
• ONE EXTRA OF EVERYTHING

3. VALUE ENGINEERING = N+1
• N+1 IS VALUE ENGINEERING OF REDUNDANCY
• ADDRESSES ONE OR MORE FAILURES MODES BUT NOT ALL
• VE OPTION EXAMPLES:
• SHARED UNIT COOLER(S) = (2) CONDENSING UNITS AND (1) UNIT COOLER SET (2 EVAPS)
• SINGLE CONDENSING UNIT WITH ADDITIONAL COMPRESSOR
• ADDITIONAL FAN(S) ON UNIT COOLER

4. N+1 PROS AND CONS
PROS
• LOWER INITIAL COST
• LESS MECHANICAL AND ELECTRICAL INFRASTRUCTURE
CONS
• CARRIES MORE RISK (HAS MORE SINGLE POINTS
OF FAILURE)
• TRULY NOT REDUNDANT (PARTIAL
REDUNDANCY)
• POTENTIALLY USES MORE POWER (HIGHER
OPERATING COSTS)
• REQUIRES MORE MONITORING POINTS TO
KNOW IF THERE IS A COMPONENT FAILURE
• COMPLICATED/CONFUSING SPECS
• FALSE SENSE OF SECURITY
• POTENTIAL CONFLICTS/CHANGE ORDERS
• VALIDATION PROTOCOL
DEVELOPMENT/EXECUTION

5. 2N PROS AND CONS
PROS
• LOWEST RISK OPTION
• BEST PERFORMANCE (CONCURRENT
OPERATION CAPABLE)
• BEST UNIFORMITY DURING SYSTEM FAULT
• ALLOWS FOR A WARNING TO TRIGGER
BACK-UP SYSTEM AVOIDING TEMPERATURE
EXCURSIONS
• SIMPLE TO UNDERSTAND (SPEC NOT LEFT
UP TO INTERPRETATION)
• VALIDATION PROTOCOL
DEVELOPMENT/EXECUTION
CONS
• HIGHEST INTIAL COST
• REQUIRES MORE INFRASTRUCTURE

6. WHY DOES IT MATTER?
• System failure notification
• Minimizing risk profile
• Reputation (no rework, getting it right the first time)
• Litigation (no rework, getting it right the first time)

7. RECOMMENDATION
BEST PRACTICE:
• 2N (100% REDUNDANCY)
• TWO SEPARATE POWER FEEDS (ONE FOR SYSTEM A AND ONE FOR SYSTEM B)
• CRITICAL SPARE PARTS INVENTORY
• REMOTE ALARM
• “BELTS AND SUSPENDERS” – MISSION-CRITICAL APPLICATIONS
• 2N CONTROLLERS
• 2N HUMIDITY
• 3N MECHANICAL
• NON-MECHANICAL BACK-UP COOLING (LN2)

8. West Coast Representative
Margaret Stava
BioPharmEquip LLC
margaret@biopharmequip.com
562 355-5859