Choosing the wrong capacity PSA oxygen generator is a costly
mistake. Too small, and your patients face oxygen shortage during peak demand.
Too large, and you have paid for capacity you will never use. This guide walks
you through the exact process of calculating the right PSA oxygen generator
size for your hospital — based on bed count, ICU requirements, operation
theatre load, and future expansion plans.
Why Capacity Matters More Than Brand
Many hospital administrators focus on brand and price when
buying a PSA oxygen generator. Capacity — the oxygen output in litres per
minute (LPM) — is actually the most critical specification. A well-branded
generator of the wrong size will fail to meet your needs just as surely as a
poor-quality one.
The right capacity ensures continuous oxygen supply at peak
demand (when all ICU patients, OT patients, and emergency cases are running
simultaneously) with a 20–30% buffer for growth.
Step 1: Understand Your Hospital's Oxygen Consumption Points
Every hospital has multiple oxygen consumption points. Map
them before calculating:
ICU and Critical Care
ICU patients on ventilators or high-flow oxygen therapy
consume 8–15 LPM continuously. This is your baseline high-demand area. Count
your total ICU and HDU beds.
Operation Theatres
Each active OT requires oxygen for anaesthesia machines and
patient support. Typical OT oxygen consumption: 5–10 LPM per OT during active
surgery. If you run 3 OTs simultaneously, budget for 30 LPM from OT alone.
Emergency Department
Emergency departments have unpredictable but high peak demand.
Budget 15–20 LPM for a medium-sized emergency department.
General Wards
General ward patients use oxygen intermittently — not all
patients need it at the same time. Typical planning figure: 1.5–2 LPM per ward
bed (average across all ward beds, accounting for actual usage patterns).
Neonatal and Paediatric ICU
NICU and PICU units use blended oxygen at precise
concentrations. Budget 5–10 LPM per NICU bay.
Step 2: Calculate Your Peak Demand
Peak demand is the maximum oxygen your hospital will ever need
at one moment. Use this formula:
•
ICU beds × 12 LPM (use 12 as a conservative average)
•
Active OTs × 8 LPM
•
Emergency department: fixed budget of 20 LPM
•
General ward beds × 1.5 LPM
•
NICU/PICU bays × 8 LPM
Add all these together. Then add 25% buffer for growth and
unexpected spikes. The result is your minimum required PSA generator output in
LPM.
Quick Reference: PSA Generator Capacity by Hospital Size
10–30 beds (small hospital or nursing home)
Recommended capacity: 50 LPM. Suitable for facilities with 1–2
ICU beds, no dedicated OT, and light general ward oxygen use. CistrOx 50 is
ideal for this segment.
30–60 beds (medium hospital, district level)
Recommended capacity: 100 LPM. Covers 4–6 ICU beds, 1 active
OT, a small emergency department, and general ward supply. CistrOx 100 is the
most popular model in this segment.
60–120 beds (large hospital)
Recommended capacity: 200 LPM. Handles a full ICU, 2–3
simultaneous OTs, emergency department, and general ward supply. CistrOx 200 is
designed for this category.
120–250 beds (tertiary hospital)
Recommended capacity: 300–400 LPM. Multiple ICUs, 4–6 OTs,
large emergency department, NICU. CistrOx 300 or 400 systems.
250+ beds (large teaching or district hospital)
Recommended capacity: 500 LPM or a dual-system setup. CistrOx
500 or a parallel twin-system configuration for redundancy.
Step 3: Plan for Future Expansion
A PSA generator is a 15–20 year asset. Do not size it for
today's hospital — size it for where you will be in 5 years.
If you currently have 60 beds and plan to expand to 120 beds,
invest in a 200 LPM system now. Running at 60% capacity for the first 2 years
is far cheaper than a complete upgrade or parallel installation later.
Cistron's CistrOx systems are modular — additional capacity
can be added as standalone units connected to the existing buffer and pipeline
infrastructure.
Step 4: Check Plant Room Requirements
A PSA oxygen generator needs a dedicated plant room.
Requirements vary by capacity:
•
50–100 LPM: minimum 10 feet × 10 feet (100 sq ft),
ceiling height 10 feet minimum
•
200 LPM: minimum 12 feet × 15 feet (180 sq ft)
•
300–500 LPM: minimum 15 feet × 20 feet (300 sq ft)
The plant room must be ventilated, dust-free, and away from
flammable materials. Cistron's site assessment team will inspect and approve
your plant room as part of the pre-installation process.
Step 5: Understand Redundancy Options
For critical care facilities, a single PSA unit with a
cylinder bank backup is the minimum acceptable setup. Larger hospitals often
install dual PSA systems in parallel — one primary, one standby — for complete
redundancy.
Cistron CistrOx systems support integration with cylinder
manifold backup systems, automatic switchover, and low-pressure alarm systems
connected to your nurse station.
Common Mistakes When Sizing a PSA Generator
•
Sizing for current demand only — ignores growth
•
Using average demand instead of peak demand
•
Ignoring OT oxygen demand (often the largest single
consumer)
•
Not accounting for NICU/PICU high-flow requirements
•
Buying on price and getting an undersized system
How Cistron Helps You Get the Sizing Right
Cistron's medical oxygen specialists offer a free site
assessment service for hospitals considering a PSA generator investment. During
the assessment, our engineer will map your oxygen consumption points, calculate
your peak demand, review your plant room, and recommend the right CistrOx
model.
There is no obligation. We provide a detailed recommendation
report that you can use even if you decide to buy from another supplier. Our
goal is to ensure every hospital in India has the right oxygen infrastructure.
Conclusion
Choosing the right PSA oxygen generator is a technical decision with a very clear methodology. Start with peak demand, add a 25% buffer, plan for 5-year expansion, and verify plant room requirements. The right capacity from a certified manufacturer is the foundation of reliable oxygen supply for your hospital.