2N vs N+1
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The document discusses two redundancy approaches for controlled environmental rooms: 2n (100% redundancy) and n+1 (partial redundancy). It outlines the pros and cons of each, with 2n providing lower risk and best performance at a higher initial cost, while n+1 offers lower costs but greater risk and complexity. The recommendation favors 2n for critical applications, emphasizing the importance of system reliability and risk management.
2N vs N+1
- 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