NFPA 20 and NBR 16704 Fire Pump: Systems, Applications and Selection

1. Fire pump standards: NFPA 20, NBR 16704 and NBR 13714

NFPA 20 (Standard for the Installation of Stationary Pumps for Fire Protection) is the NFPA standard for installing stationary fire protection pumps. It covers centrifugal, vertical turbine and positive displacement pumps, electric and diesel drives with their controllers, the power supply, the fuel tank and acceptance testing. NBR 16704 sets the requirements for stationary pump sets serving automatic fire protection systems.

NBR 13714 (hydrant and hose reel systems) covers the system the pump supplies and therefore the demand. The ABNT Catalog record lists it as in force, confirmed on 25 April 2024. What sets the system type, flow, pressure and fire water reserve required on the job is the state Fire Department Technical Instruction, in Tables 2 and 3 of São Paulo's IT 22 and Goiás' NT 22; the NBR 13714 article gives the values with the state of each one.

Each Brazilian state publishes the regulations its Fire Department applies to design review and inspection. In São Paulo, CBPMESP Technical Instruction IT 22 covers hydrants and hose reels and gathers the fire pump rules in Annex C; IT 23 covers automatic sprinklers. In Goiás, CBMGO NT 23 requires sprinkler pump sets to follow Annex C of NT 22 and NBR 16704, and requires those pumps to operate under positive pressure, with no priming tank.

These rules apply in the jurisdiction that published them.

1.1 NBR 16704: installation of the pump set

According to the ABNT Catalog record, NBR 16704 sets the minimum requirements for the selection and installation of stationary pump sets for automatic fire protection systems, and is in force. It is the Brazilian reference for installing the set, alongside NFPA 20. In Goiás, NT 23 requires sprinkler pump sets to follow Annex C of NT 22 and NBR 16704.

The record states that the standard has a certification program. The certification of a model is proven only by the certificate issued for it; FB declares the pump set design in conformity with NFPA 20.

2. Technical guides by occupancy type

Occupancy changes the input data, not the selection method. The local rule classifies the building by built area and occupancy and thereby sets the system type and the minimum reserve; in São Paulo, that classification is in Table 3 of IT 22. The pump comes from the hydraulic calculation in the design report, with the two most unfavourable jets in simultaneous use, and IT 22 does not accept a reference to another project to justify the sizing.

The guides below detail the decisions for each type of building. Use them with the current revision of the design report to prepare the technical enquiry.

• Warehouses and distribution centres: protection depends on the goods and the storage arrangement; in Goiás, NT 23 requires any storage, even temporary, to be protected under NBR 16981.
• Shopping centres, hospitals and residential buildings: occupied buildings with hydrants and, depending on classification, automatic sprinklers; IT 22 in São Paulo (C.1.2) and NT 22 in Goiás (C.1.1) require a pump room with access all around the pumps and space to remove any of them.
• Power plants, refineries and terminals: in São Paulo, protection of tanks and tank farms follows IT 25; when those tanks are separated from other buildings under IT 25, the hydrant reserve is not added to the reserve of the cooling and foam systems (IT 22, 4.12.2 and 4.12.6).
• Preassembled skid: the set is mounted on a metal baseplate according to the contracted arrangement; the suction, discharge, power and exhaust interfaces are defined in the design, and the components and scope of supply in the proposal.

3. Technical guides by system component

The set comprises the main pump, the pressure maintenance (jockey) pump, the driver, the control panel and the valves.

Goiás' NT 22 defines the fixed pump as the one meant to deliver water to the fire-fighting systems (item 4.4), the booster pump as the one that supplies the hydraulically most unfavourable hydrants or hose reels when the elevated reservoir alone cannot supply them (item 4.3) and the jockey pump as the centrifugal hydraulic device that keeps the system pressurized within a preset range (item 4.5).

In São Paulo, Annex C of IT 22 sets rules that apply to any driver. The fire pump serves that purpose only and is protected against mechanical damage, weather, chemicals, fire and moisture. The main pump is directly coupled through a flexible coupling, without belts or chains, with an isolating valve upstream and a check valve plus an isolating valve downstream.

After an automatic start, shutdown is manual only, at the panel in the pump room, and the pump must reach full operating speed in about 30 s.

• Electric motor: power supply independent of the general load, a switch marked “ALIMENTAÇÃO DA BOMBA DE INCÊNDIO – NÃO DESLIGUE” (fire pump supply – do not switch off), magnetic starting and acceleration within 10 s (IT 22, C.2.7, C.2.11 and C.2.18).
• Diesel engine: full-load operation for 6 uninterrupted hours, a speed governor holding rated speed within 10%, two battery sets with a dual charger, and recharge of a discharged battery within 24 h (IT 22, C.3.1.4, C.3.2, C.3.10 and C.3.11).
• Jockey pump: required in São Paulo when the network has more than six outlets, except with an elevated reservoir; maximum flow of 20 L/min and maximum pressure equal to the main pump shutoff, with about 100 kPa (10 m of water) recommended between sequential starts (IT 22, C.1.15 and C.1.15.1).
• Sprinklers and hydrants: each system’s demand comes from its own standard, and IT 22 allows reserves to be interconnected under the parameters of IT 23.

4. Decision flow: which guide to use at each project stage

The starting guide depends on the project stage. At concept stage, begin with the occupancy guide, which organizes classification, required systems and input data. At specification stage, move on to the component guides and the sizing article. During construction and acceptance, use the pump room, commissioning and maintenance guides.

5. Sizing: flow, pressure, NPSH and curve

Design flow is the largest simultaneous demand in the design report. In São Paulo, hydrant and hose reel systems range from type 1 to type 5 in Table 2 of IT 22, with a minimum flow of 100 to 600 L/min at the valve of the most unfavourable hydrant, and the calculation considers the two most unfavourable jets in simultaneous use.

For automatic sprinklers, the hazard classification and the design area come from the system’s technical standards; in Goiás, NT 23 accepts NFPA 13 where Brazilian standards are silent.

Total head is the sum of the elevation difference, the friction losses and the pressure required at the most unfavourable point. IT 22 accepts Darcy-Weisbach or Hazen-Williams and gives the new-pipe C factor by material: 100 for unlined cast or ductile iron and for black steel in dry systems, 120 for black steel in wet systems and for galvanized steel, 140 for cement-lined cast or ductile iron and 150 for copper and plastic.

Working pressure at the nozzles may not exceed 100 m of water (1,000 kPa), and IT 22 does not recommend fire pumps above 100 m of water (1 MPa).

On the suction side, IT 22 limits velocity to 2 m/s under suction lift and 3 m/s under positive suction, and to 5 m/s in the rest of the piping (items 4.8.11 and 4.8.12 of São Paulo's IT; items 5.8.9 and 5.8.10 of Goiás' NT). Under suction lift, available NPSH is calculated at 1.5 times the system rated flow and must be equal to or greater than the NPSH required from the pump curve at that flow.

IT 22 prefers positive suction and only accepts pumps with suction above the water level in type 1, 2 and 3 systems, with a dedicated suction pipe, a foot valve with strainer and a priming tank.

The curve must cover the design report demand within the range the adopted design standard allows for the pump. The readings of the field acceptance test come from the testing chapter of the adopted standard (Chapter 14 in NFPA 20): ask for the procedure and the test points in the proposal.

In São Paulo, IT 22 requires pumps rated above 600 L/min to have a continuous water flow through a 6 mm tube or orifice plate taken from the volute, to prevent overheating.

6. Industrial main fire pump: what to verify in the proposal

A catalogue centrifugal pump may have the same rated point as the design and still not qualify as a fire pump. What decides is the curve from shutoff to 150% of flow, the coupling, the driver, the control panel and the set’s documentation. The table sets out what the rule requires and the evidence the proposal must include.

7. Documentation for the Fire Department inspection (AVCB)

In São Paulo, the AVCB is issued by the Fire Department for the building (State Decree 69.118/2024, art. 3, XI). It belongs to the building, not to the pump: the supplier delivers the set’s documents, and the design and installation complete the process. IT 22 requires a design report with calculations, sizing and an isometric view of the piping, and does not accept a reference to another project to justify any information.

After the inspection, the São Paulo regulation assigns maintenance and periodic testing of the safety measures to the owner or the party responsible for use, in accordance with the specific technical standards (State Decree 69.118/2024, art. 15, II). The list below gathers the set documents that feed the process.

• Datasheet and Q×H curve for the offered model, impeller and speed.
• Pump nameplate with manufacturer, serial number, model, rated flow and pressure, speed and impeller diameter (IT 22, C.2.15).
• Electric motor nameplate with manufacturer, type, model, serial number, power in CV, speed, voltage, current and frequency (C.2.16), or diesel engine nameplate with continuous-duty power and rated speed (C.3.8).
• Control panel with dimensional drawings, layout, wiring diagram, terminal strip, internal diagram and bill of materials (C.2.18.4).
• Dimensional drawing of the set and of the site interfaces.
• Installation, operation and maintenance manuals for the equipment.
• System commissioning report; IT 22 provides a template in Annex F.

8. Planning stages: from order to acceptance

Timing depends on approvals, components and site readiness, and is confirmed in the proposal. For field acceptance, the pump test follows the adopted standard's procedure, with the readings recorded point by point.

9. Mistakes to avoid in fire pump projects

Each item below has an objective check in the design report, the proposal or the installation. Record the answer in the supply documentation. References to IT 22 apply to São Paulo.

• Selecting on the rated point alone, without checking the demand up to 150% of flow and the shutoff against the adopted standard’s envelope.
• Calculating available NPSH at rated flow: under suction lift, IT 22 requires 1.5 times the system rated flow.
• Designing suction above the water level in a type 4 or 5 system: IT 22 only accepts that condition in types 1, 2 and 3.
• Using belts or chains between driver and main pump, where IT 22 requires direct flexible coupling.
• Connecting the electric pump downstream of the building main switch, so that a general shutdown also cuts the pump; IT 22 requires a supply independent of the general load.
• Programming automatic shutdown of the main pump: after starting, shutdown must be manual, at the panel in the pump room.
• Sizing the diesel tank without the selected engine’s consumption or without the applicable rule (NFPA 20 or IT 22).
• Setting the jockey pump above the main pump shutoff or without a differential between starts; IT 22 recommends about 100 kPa (10 m of water) between sequential starts.
• A pump room without access all around the pumps, without space to remove any of them, or housing machinery other than water-based fire protection or domestic water pumps.
• Applying another state’s rule or copying another project: IT 22 does not accept references to another project in the design report.