Teknik·12 min read
NOVEC 1230 Clean Agent Suppression: Design Concentration, Extended Height and Volume Calculation
The details that make a NOVEC 1230 system work on site: ISO 14520-5 design concentrations, the nozzle height limit and the extended-height increased concentration that kicks in above 4.27 m, agent quantity and net volume calculation, the widest NOAEL safety margin among clean agents, and the GWP ≈ 1 environmental advantage.
A-Pro Mühendislik
NOVEC 1230 (chemically FK-5-1-12) is the newest generation of clean gaseous suppression agent for electrical/electronic enclosures where water would cause damage. Two features set it apart from other clean agents: one of the widest safety margins for occupied spaces (NOAEL 10%) and a far superior environmental profile compared with HFCs (GWP ≈ 1). We covered which agent to choose in which situation in Gas Suppression: Design and Agent Selection, and examined the FM200 design and volume calculation in a separate article. Here we look at NOVEC 1230 from an engineering standpoint and focus on a point most projects miss: the nozzle height limit and the extended-height (increased) design concentration that comes into play for enclosures taller than 4.27 m.
Suppression mechanism and discharge time
NOVEC 1230 extinguishes fire mainly by absorbing heat (physically), and partly by interfering with the combustion chain reaction. Its most distinctive physical trait: it is a liquid at room temperature (boiling point ≈49 °C) and behaves like a “dry fluid” — on discharge it evaporates roughly 50 times faster than water, leaves no residue and does not harm electronics. It is stored in the liquid phase, super-pressurised with nitrogen (typically 25 / 42 / 50 bar); on release it rapidly turns to gas and fills the enclosure homogeneously.
The critical design rule is that discharge completes in 10 seconds or less: (1) to reach design concentration quickly and suppress the fire early, and (2) to shorten the agent’s exposure to flame and minimise the formation of decomposition products (HF). NOVEC 1230 is a gas about 11 times heavier than air; this density aids uniform distribution but also raises the risk of stratification in tall enclosures — which is precisely the technical basis of extended height.
Hazard classes and design concentration (ISO 14520-5)
In Turkey, gas suppression design is based on TS ISO 14520. ISO 14520 defines the design concentration by applying a safety factor (×1.3) to the experimentally measured extinguishing concentration, and uses three hazard classes (NFPA 2001’s “Class C” is not a separate class in ISO; it is handled within Class A – High hazard). The standard ISO 14520-5 (Table 4) values for NOVEC 1230 (FK-5-1-12):
| Class | Concentration basis (ISO 14520-5) | NOVEC 1230 design concentration |
|---|---|---|
| Class A — Surface | Highest of wood crib / PMMA / PP / ABS extinguishing values × 1.3 | 5.3% |
| Class A — High hazard | Greater of surface Class A or 95% of the Class B design | 5.6% |
| Class B — Flammable liquid | Heptane (cup-burner) extinguishing value × 1.3 | 5.9% |
- Class A – Surface: Surface burning of solid combustibles (paper, wood, plastic, cable insulation). NOVEC’s highest extinguishing value (PMMA 4.1%) × 1.3 = 5.33% → 5.3%.
- Class A – High hazard: Enclosures with a dense fuel load or where equipment stays energised. ISO 14520-5 defines this class as the greater of surface Class A (5.3%) or 95% of the Class B design (0.95 × 5.9% = 5.6%) → 5.6%.
- Class B – Flammable liquid: Heptane cup-burner value (4.5%) × 1.3 → 5.9%.
Which class a space falls into — the definitions of the three classes, the four high-hazard conditions of ISO 14520-1 clause 7.5.1.3 (cable bundle >100 mm · tray fill >20% · tray stacks <250 mm apart · energised >5 kW) and the “which space, which class” table — is agent-independent; for the detail, see the hazard-class determination section of our Gas Suppression: Design and Agent Selection article. In brief: energised data center/server/telecom rooms meet condition 4 (energised + >5 kW) by default and are therefore treated in practice as Class A – High hazard (5.6%); the Surface (5.3%) value is for de-energised, low-cable-load spaces (archives, small electrical rooms).
Extended height: the nozzle height limit and the increased concentration
This is the most critical heading of this article. The design concentrations in the ISO 14520-5 table apply to a specific maximum protected height over which the agent, leaving the nozzle, can fill the enclosure homogeneously within ≤10 s. NOVEC 1230 nozzles are listed against this height in their UL/FM/EN approvals; for the Viking VSN 1230 nozzle for example:
- Standard maximum protected height: 4.27 m (minimum 0.3 m).
- With the extended-height listing: up to 5.45 m. But at this height the nozzle must distribute the agent homogeneously across a greater elevation difference and prevent stratification, so the design concentration is increased (increased minimum design concentration).
The increased values used for extended height (5.45 m) on an ISO 14520-5 basis, compared with the standard values:
| Class | Standard (≤ 4.27 m) | Extended height (4.27–5.45 m) |
|---|---|---|
| Class A — Surface | 5.3% | 5.7% |
| Class A — High hazard | 5.6% | 5.9% |
| Class B — Flammable liquid | 5.9% | 6.2% |
Three engineering consequences follow:
- Height classification directly increases the agent quantity. In a server hall exceeding 4.27 m, using the extended 5.9% instead of the standard 5.6% raises the required agent mass and cylinder count. Missed on paper, the system fails at site acceptance.
- Above 5.45 m a single nozzle level is not enough. Multi-level nozzle layouts, intermediate nozzle tiers or subdivision of the volume are required; you cannot go outside the nozzle manufacturer’s approval scope.
- Height and voids are assessed together. When raised-floor and suspended-ceiling voids are included in the protected volume, the total elevation difference grows; the extended-height threshold is checked against this total.
In short: one of the first questions in a NOVEC design should be “does the enclosure’s real protected height exceed the nozzle listing’s standard limit (typically 4.27 m)?” If it does, the extended-height increased concentration and nozzle layout are selected accordingly.
NOAEL and LOAEL: the safety margin is NOVEC’s strongest suit
- NOAEL (No Observed Adverse Effect Level): the highest concentration producing no observable adverse effect in humans. For NOVEC 1230 it is 10%.
- LOAEL (Lowest Observed Adverse Effect Level): the lowest concentration at which an adverse effect begins. For NOVEC 1230 it is > 10%.
NOVEC 1230’s design concentration is 5.3–5.9% (at most 6.2% for extended height); a very wide safety margin remains up to the NOAEL (10%). This margin is one of the highest among clean agents and makes NOVEC especially preferred for normally occupied server/control rooms. The comparison is striking: in FM200 the high-hazard concentration (8.5%) sits only ≈0.5 points below its NOAEL (9%), whereas in NOVEC the high hazard (5.6%) is ≈4.4 points below its NOAEL (10%). Where human safety is critical, this difference is decisive.
Environmental profile: GWP ≈ 1 and F-gas assurance
NOVEC 1230 (FK-5-1-12) has zero ozone-depletion potential (ODP = 0), a global-warming potential of about 1 (GWP ≈ 1) and a very short atmospheric lifetime of about 5 days. Where HFC-based FM200 has a GWP of ≈3220, NOVEC is effectively considered “climate-neutral.” This is not just an environmental preference but a regulatory assurance: the EU F-gas regulation is phasing down HFCs; NOVEC is unaffected by these restrictions. For long-life facilities (data centers, critical infrastructure) this matters for the system’s future serviceability.
Agent quantity and volume calculation
The required NOVEC 1230 agent mass is calculated with the TS ISO 14520 / NFPA 2001 formula:
W = (V / s) × (C / (100 − C))
- W = required agent mass (kg)
- V = protected net free volume (m³)
- C = design concentration (%)
- s = specific volume of the agent (m³/kg); per ISO 14520-5, s = 0.0664 + 0.000274 × T (T = enclosure temperature °C)
Example: a server room of 100 m² floor area and 3.0 m height (V = 300 m³), T = 20 °C. Because the equipment stays energised during discharge the space is Class A – High hazard, and since the height is below 4.27 m the standard concentration C = 5.6% is used:
s = 0.0664 + 0.000274 × 20 ≈ 0.0719 m³/kg
W = (300 / 0.0719) × (5.6 / 94.4) ≈ 4173 × 0.0593 ≈ ≈248 kg of NOVEC 1230
Had the same room exceeded 4.27 m (say 5.0 m), the extended-height listing would apply and the concentration would rise to 5.9% (increasing mass and cylinder count). Note that NOVEC requires more mass than FM200 (which in the same room, high hazard 8.5%, would be ≈203 kg); this is due to NOVEC’s higher molecular mass and density. As temperature falls the specific volume shrinks and more gas is needed for the same volume, so the enclosure’s lowest design temperature is used.
Altitude above sea level and the atmospheric correction
The correction is agent-independent and applies only above ≈1,000 m (TS ISO 14520-1 cl. 7.7); the agent mass is multiplied by the Table 5 factor. For example, the room above draws no correction in Ankara (≈900 m, ≈248 kg); at a facility 1,500 m high it becomes 248 × 0.830 ≈ ≈206 kg. For the full factor table and rationale, see the shared calculation rules in our Gas Suppression: Design and Agent Selection article.
What may — and may not — be deducted from the volume?
Only permanent structural elements (reinforced-concrete columns/beams) may be deducted from the gross volume; movable equipment such as cabinets, panels and server racks is not deducted — if removed, the free volume grows and the concentration drops below the design value. The calculation is always based on the largest (safest) free volume. For detail, see the shared calculation rules in our pillar article.
Nozzle layout and coverage
The NOVEC nozzle’s coverage area and the extended-height limit are engineered together. For the Viking VSN 1230 nozzle (EN/ISO/FM/UL) the typical single-nozzle limits are: maximum area ≈95 m², radius ≈10.9 m for 180°, ≈6.9 m for 360°, maximum height 4.27 m (extended 5.45 m), minimum height 0.3 m. In practice:
- First the required agent quantity for the protected volume, and the nozzle count from it, are calculated.
- Site conditions are then checked: if the spray is shadowed by cable trays, ducts or obstructions, more nozzles than the area calculation gives may be needed — especially over cable runs. Otherwise “dead zones” go unprotected.
- If raised-floor and suspended-ceiling voids are protected, a separate nozzle is placed at each level.
Suspended ceiling and raised floor
Server and electrical rooms usually contain a suspended ceiling and a raised floor. Voids that hold a fuel load (cable trays, power/data cables) or form part of the airflow path are included in the protected volume. Two methods are used: (1) integrated volume — if the void is in free air exchange with the room it is combined with the room volume and a nozzle is placed at each level; (2) separate zone — if the void is a gas-tight compartment it is treated as its own protected volume with a dedicated nozzle line. In both cases these volumes are added to the agent quantity, and the extended-height threshold is checked against the total elevation difference.
System devices and damper automation
The core logic of the contact-output pressure gauge, the pressure switch and the ventilation/damper automation is common to all gas systems; for the detail and the correct discharge sequence, see the shared equipment and automation section of our Gas Suppression: Design and Agent Selection article. In brief: the pressure gauge monitors cylinder pressure and verifies the system is ready to fire; the pressure switch senses discharge and triggers the alarm/HVAC shutdown/damper closure; the dampers are closed before discharge and kept closed throughout the hold time (≈10 min).
NOVEC 1230-specific points: discharge completes in ≤10 seconds; the post-hold purge ventilation exhausts residual agent along with any decomposition products (HF, etc.). The overpressure relief damper is adequate at a standard size for halocarbons.
Design and installation checklist
- Protected-height check: does the enclosure’s real elevation difference exceed the nozzle listing’s standard limit (typically 4.27 m)? If so, select the extended-height increased concentration (5.9% instead of 5.6% for Class A – High hazard) and nozzle layout; above 5.45 m a multi-level solution is required.
- Class determination: energised data center/server/telecom spaces are treated as Class A – High hazard (5.6%); the surface value (5.3%) is for de-energised, low-cable-load spaces.
- Net free volume: deduct only columns/beams; do not deduct equipment.
- Altitude correction: applied only above ≈1,000 m (TS ISO 14520 cl. 7.7); below that the factor is 1.00.
- Voids: include suspended-ceiling/raised-floor voids in the volume; check the extended-height threshold against the total elevation.
- NOAEL margin: the design concentration (5.3–6.2%) is well below the NOAEL (10%); NOVEC offers a wide margin for occupied spaces.
- ≤10 s discharge: nozzle and pipe hydraulics are sized to achieve this.
- Tightness and door-fan test: hold time is verified by a door-fan test; cable penetrations and door undercuts are sealed.
- Equipment supervision and scenario integration: monitor agent loss with the gauge, confirm discharge with the pressure switch; detection → alarm → HVAC/damper → discharge → hold → purge are built into one scenario.
- Periodic maintenance: cylinder weighing/pressure checks are done regularly; for detail see our periodic maintenance of fire systems article.
Summary
Success in NOVEC 1230 design means selecting the correct design concentration per ISO 14520-5 (Class A – Surface 5.3%, High hazard 5.6%, Class B 5.9%) and assessing the enclosure height together with the nozzle listing: if the protected height exceeds the standard limit (typically 4.27 m), the extended-height increased concentration (5.7% / 5.9% / 6.2%) applies and enlarges the agent quantity. NOVEC’s core advantages are not mass economy but the widest NOAEL safety margin among clean agents and a GWP ≈ 1 environmental profile. For the field where these decisions apply most intensively, see our Data Center Fire Safety article; contact us for facility-specific NOVEC 1230 design and volume calculation with a free site survey within Ankara.
This content is for information only. Binding calculation and design for your facility require project-based work with a fire engineer under TS ISO 14520 / NFPA 2001 and the relevant nozzle approval listing.
© 2026 A-Pro Mühendislik. This is original technical content produced by A-Pro Engineering; all rights reserved. Copying, reproducing or republishing it in whole or in part without attribution and permission is prohibited.
Frequently asked questions
How does the NOVEC 1230 design concentration change with hazard class?+
The basis in Turkey, TS ISO 14520-5, applies a ×1.3 safety factor to the extinguishing concentration and defines three classes. For NOVEC 1230 (FK-5-1-12) the standard values (nozzle height ≤ 4.27 m) are: Class A – Surface 5.3%; Class A – High hazard 5.6%; Class B – Flammable liquid 5.9%. Data center/server/telecom spaces holding energised equipment satisfy the 4th high-hazard condition (energised + > 5 kW) by default, so in practice they are treated as Class A – High hazard (5.6%).
What is extended height and why does it increase the design concentration?+
NOVEC 1230 nozzles are UL/FM/EN listed for a specific maximum protected height (in the Viking VSN 1230 example, 4.27 m standard). If the enclosure exceeds this height — up to 5.45 m with an extended-height listing — the design concentration is increased so the nozzle can distribute the agent homogeneously across the greater height within ≤10 s and prevent stratification (NOVEC is ≈11 times heavier than air). The ISO 14520-5 based extended values are: Class A – Surface 5.7%; Class A – High hazard 5.9%; Class B 6.2%. Above 5.45 m a single nozzle level is not enough; multi-level nozzles or an alternative solution are required.
Why is NOVEC 1230 considered safe for occupied spaces?+
NOVEC 1230 has a NOAEL of 10% and a LOAEL of > 10%. Since typical design concentrations are 5.3–5.9% (at most 6.2% for extended height), a wide safety margin remains up to the NOAEL. This margin is one of the highest among clean agents and makes NOVEC preferred for normally occupied server/control rooms; by comparison, FM200's high-hazard concentration (8.5%) sits much closer to its NOAEL (9%).
Why does NOVEC 1230 require more agent mass than FM200?+
NOVEC 1230 extinguishes at a lower volumetric concentration (e.g. 5.6%), but its molecular mass (316) and density (≈11 times that of air) are higher than FM200's (170). So the mass required per cubic metre (kg/m³) is greater: about 0.825 kg/m³ at 20 °C for 5.6%. The same 300 m³ enclosure needs ≈203 kg of FM200 (high hazard 8.5%) but ≈248 kg of NOVEC (5.6%). NOVEC's advantage is not mass economy but its safety margin and environmental profile.
What is the environmental profile of NOVEC 1230?+
NOVEC 1230 (FK-5-1-12) has zero ozone-depletion potential (ODP = 0), a global-warming potential of about 1 (GWP ≈ 1) and a very short atmospheric lifetime of roughly 5 days. This makes it far more environmentally benign than HFC-based FM200 (GWP ≈3220) and it is not subject to the phase-down the EU F-gas regulation imposes on HFCs; for long-life facilities this is an important future-proofing benefit.
What can be deducted from the enclosure volume in a NOVEC 1230 calculation?+
Only permanent (non-removable) structural elements — impermeable, fixed building components such as reinforced-concrete columns and beams — may be deducted from the gross volume. Movable equipment such as cabinets, panels, server racks, shelving and machinery is NOT deducted, because if it is later removed the free volume grows and the concentration drops below the design value. The calculation is always based on the largest (safest) free volume, as if the equipment were not there.
Does altitude above sea level affect the NOVEC 1230 agent quantity?+
Yes, but only at high altitude. TS ISO 14520-1 (clause 7.7) requires the atmospheric correction only when ambient pressure deviates more than 11% from sea level — roughly above 1,000 m. Up to ≈1,000 m the correction factor is 1.00; above that the agent mass is multiplied by the Table 5 factor (1,500 m → 0.830). This correction is agent-independent; the same factors apply to NOVEC and FM200.
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