1. Why dual-diesel: the redundancy required by NFPA 20 chapter 11
NFPA 20 chapter 11 is dedicated specifically to facilities where fire-fighting system reliability must be maximum: refineries, flammable liquid terminals, petrochemical plants, and large power plants. In these facilities, relying exclusively on an electric main pump is an unacceptable risk — a local electrical failure, a controller short circuit, or even phase reversal on start-up can defeat the combat at a critical moment. The technical response is 2×100% redundancy: two main pumps, each capable of delivering full design flow, driven by independent diesel engines with separate fuel tanks, separate batteries and separate controllers. This configuration is known in the sector as dual-diesel.
Operation logic is simple: pump A starts first on demand (pressure drop), runs for a few minutes, and if pressure continues to drop or failure is detected, pump B starts in parallel. If pump A fails mechanically, pump B takes over the entire demand. The two controllers are interconnected by mutual supervision signal, and both have manual bypass in case of primary controller failure. The entire installation is designed so that no single component — fuel tank, battery, cable, supply valve — can simultaneously compromise both pumps. It is the N+1 philosophy applied rigorously.
2. Classified area motors: Ex d IIB T3 and INMETRO certification
In a refinery or a fuel terminal, the fire-fighting pump house is frequently near classified areas — Zone 1 or Zone 2 per ABNT NBR IEC 60079-10-1, which deals with electrical zoning in areas with flammable gases or vapors. Any auxiliary electric motor (jockey pump, forced pump-house ventilation, drain pumps, instrumentation compressors) must be certified for the zone where it will be installed. The technical standard is Ex d IIB T3: "d" indicates a flameproof enclosure; "IIB" covers most refinery gases; "T3" is the temperature class corresponding to surfaces not exceeding 200 °C, appropriate for naphtha, gasoline and kerosene.
In Brazil, European ATEX certification has no legal validity — INMETRO certification per Ordinance 179/2010 is required. Ex d motors used in FB Bombas skids for refineries come from certified suppliers like WEG (W22X line for classified areas) or Siemens (1MB series), both with INMETRO certification issued by an accredited body. The delivered skid includes certification documentation for each electrical component, facilitating project approval by the refinery technical staff and insurer audit.
3. Foam proportioner: flammable liquid fire-fighting
In refineries and fuel terminals, the fire to be fought is not merely solid combustion — it is primarily flammable liquid combustion. Water alone does not extinguish this type of fire; it may even worsen it, because hot water generates vapor that elevates combustion, and liquid water sinks beneath the fuel, spreading it. The technical response is mechanical foam formed by mixing water, air and foam concentrate (LGE or AFFF — Aqueous Film Forming Foam). The foam floats over the fuel, creates an isolation barrier between liquid and air, and extinguishes the fire by smothering.
The foam proportioner is the component that automatically mixes pumped water with foam concentrate in a precise proportion — typically 3% or 6% depending on concentrate manufacturer and fuel type. In an FB Bombas refinery skid, the proportioner can be inline (flow-induced), proportional dosing pumps, or membrane system — each option with advantages in simplicity or precision. The foam concentrate reservoir is sized for minimum operational autonomy per hazard classification: for fuel storage tanks, typically 30 to 60 minutes of continuous operation, which may represent several thousand liters of concentrate. Correct proportioner operation is as important as pump operation itself — a proportion error generates inadequate-quality foam that does not extinguish the fire.
4. API 2030 and Petrobras N-1203: the sector standards
Two normative documents dominate fire-fighting design in Brazilian refineries and terminals: API 2030 (Guidelines for Application of Water Spray Systems for Fire Protection in the Petroleum Industry) and Petrobras N-1203 (Fire Protection System Design in Onshore Installations). API 2030 is the international reference accepted by all major insurers for flammable liquid storage terminals. It defines flow sizing criteria, residual pressure, monitor ring arrangement around tanks, wall cooling protection (water spray), and test procedures.
Petrobras N-1203, in turn, is the company's own technical document for projects in its facilities — and any supplier wishing to deliver to a Petrobras unit must rigorously follow this standard. It establishes specific requirements on redundancy (mandatory dual-diesel in onshore processing units), minimum reservoir capacity, component certification, material traceability, and factory (FAT) and field (SAT) acceptance procedures. FB Bombas is CRCC Petrobras-qualified for fire-fighting skid supply — this registration is periodically renewed and requires manufacturing process audit, quality documentation and supply history.
5. Water intake: river, sea and the material decision
Fuel terminals and refineries are typically located on coasts or near large waterways for logistical reasons of product receipt and dispatch. This has a direct implication on fire pump selection: intake can be made directly from the river or sea instead of a dedicated reservoir. When intake is from the sea, water is corrosive to any ferrous material — cast iron and carbon steel last only a few years in continuous brine contact. The technical response is casing and impeller in 2205 duplex or super duplex depending on severity: duplex withstands chlorides in concentrations up to approximately 2000 mg/L and resists pitting; super duplex (25Cr) exceeds the 3000 mg/L range.
For river intake, the situation is different: fresh water itself is not corrosive but carries suspended solids (sand, silt, organic matter) that cause impeller erosion and suction strainer clogging. FB Bombas supplies skids for this application with reinforced bronze or duplex impellers, automatic cleaning duplex strainers, and vertical turbine pumps when river level variation is large. For power plants with dedicated cooling tower, intake is frequently from a treated internal reservoir, and standard material (cast iron ASTM A48 Class 30B with ASTM B62 bronze impeller) is perfectly adequate.
6. FAT, SAT and three-stage certification
Fire-fighting skids for refineries and terminals go through three mandatory certification stages before being put in service. The first is FAT (Factory Acceptance Test), conducted on the FB Bombas factory test bench in Cabreúva-SP. Each pump is individually tested with a complete H-Q-η-NPSHr curve measured and witnessed by the customer or an independent third party. Also tested: controller sequence, alarms, manual and automatic start, 30-minute churn test with temperature monitoring, and circulation relief valve operation. The entire test is documented in a signed and archived report.
The second stage is transport and installation at the customer site, followed by SAT (Site Acceptance Test). SAT repeats the entire FAT test sequence, now integrated with the rest of the system — piping, reservoir, monitors, sprinkler rings, foam proportioner, electrical supply. Any variation between FAT and SAT is documented and, if significant, generates a corrective procedure before final certification. The third stage is local Fire Department inspection and, in parallel, insurer audit — the latter frequently done by international third-party companies (Risk Control Associates, Marsh, WTW) that visit the site, verify compliance with contractual standards and issue a conformity report that goes into the policy file. Only after these three stages is the system considered in commercial operation.