Masdaf – YNM UL/FM fire pump with end-suction design
The YNM UL/FM fire pump is a single-stage, end-suction centrifugal pump with a spiral casing, certified to UL 448 and approved to FM 1319. The series comprises three sizes — YNM 525, YNM 825 and YNM 1531 — and covers flow rates from 11 to 284 m³/h at heads ranging from 59 to 109 m. The pump is not self-priming and operates with water at temperatures ranging from 0 to 60 °C.
What approvals does the YNM UL/FM series cover?
UL/FM approvals are issued separately for each component of the pump assembly, and these must match in the design. For the YNM UL/FM model, the specifications are as follows: pump — UL 448 and FM 1319; flanges — ANSI/ASME B16.1 Class 250, drilled with a flat mating surface; threaded connections — ANSI/ASME B1.20.1; electric motor — UL 1004-5; diesel engine, if specified in the diagram — UL 1247 and FM 1333; control cabinet — UL 218 and FM 1321 / FM 1323. Please note the FM number: for end-suction pumps, this is FM 1319, not FM 1311, which applies to split-case pumps.
Three sizes in the range
| The model | Suction flange | Discharge flange | Nominal diameter of the impeller | Mass, kg |
|---|---|---|---|---|
| YNM 525 | DN 80 (3″) | DN 50 (2″) | 250 mm | 66 |
| YNM 825 | DN 125 (5″) | DN 80 (3″) | 250 mm | 103 |
| YNM 1531 | DN 200 (8″) | DN 150 (6″) | 315 mm | 184 |
The weights given are for the pump itself, excluding the motor and frame.
How the YNM pump works
The mechanical assembly consists of a rigid shaft mounted on grease-lubricated bearings and a sealed impeller fitted within a removable bearing assembly. The assembly is connected to a spiral casing with end suction, fitted with wear rings. The bearing housing, together with the shaft and impeller, can be removed from the spiral casing for maintenance without disconnecting the pipework. The discharge pipe is positioned vertically, opposite the pump’s support feet; an additional support foot is fitted on the outer bearing side to provide rigidity. The shaft is sealed with a soft gland packing — this is a requirement for fire pumps.
What are the benefits of a remote coupling?
The pump is supplied on a frame with a flexible coupling, selected to suit the unit’s power rating and operating conditions. A remote coupling is fitted on request: this allows the pump’s rotating assembly to be removed without disconnecting the pipework or removing the motor. For a fire pump that has been on standby for years and undergoes routine inspections, this directly reduces maintenance time and costs — the packing and wear rings can be replaced without dismantling the unit.
Technical specifications for YNM UL/FM
| Parameter | Value |
|---|---|
| Type | single-stage centrifugal pump with end suction, volute casing, non-self-priming |
| Pump certification | UL 448, FM 1319 |
| Capacity | 11 – 284 m³/h |
| Pressure | 59–109 m |
| Rotational speed | 3,000 rpm |
| Suction flange | 3″ – 8″ (DN 80 – DN 200) |
| Discharge flange | 2″ – 6″ (DN 50 – DN 150) |
| Flange standard | ANSI/ASME B16.1 Class 250, flat mating surface |
| Threaded connections | ANSI/ASME B1.20.1 |
| Fluid temperature | 0–60 °C |
| Impeller | closed, with wear rings |
| Shaft seal | soft gland packing |
| Bearings | lubricated with grease, in a removable bearing assembly |
| Electric motor | in accordance with UL 1004-5 |
| Diesel engine (optional) | in accordance with UL 1247 / FM 1333 |
| Control cabinet | in accordance with UL 218, FM 1321 / FM 1323 |
| Additional certificates | CE; TSE ‘Centrifugal pump, Class 3’ |
What auxiliary connections are provided for?
The manufacturer’s specifications define the threaded ports for each model: pressure gauge and vacuum gauge — Rp1/4; casing vent — Rp3/8 for the YNM 525 and Rp1/2 for the YNM 825 and YNM 1531, gland drain — Rp1/2, casing drain — Rp3/8 for the YNM 525 and Rp1/2 for the others, seal lubrication — Rp1/2. These ports are required when the system is piped in accordance with regulations: suction and discharge pressure monitoring and drainage are mandatory components of a fire pump assembly.
Where are YNM UL/FM pumps used?
The manufacturer specifies the scope of application for this series as fire suppression systems for low, medium and high-risk applications. The three sizes cover a range from small sprinkler systems to medium-capacity installations, where UL/FM approval is specifically required rather than compliance with NFPA 20.
How does the YNM UL/FM differ from other Masdaf fire pumps?
The YNM UL/FM and YNM NFPA series share the same end-suction hydraulics but are based on different standards: the former series is approved to UL 448 and FM 1319, whilst the latter is designed in accordance with NFPA 20. The YPSP series comprises split-case, double-suction pumps designed for higher flow rates; their FM approval carries a different number, FM 1311. The YPH is a vertical in-line pump compliant with NFPA 20 for low- and medium-risk systems. The ENM stands apart: it is a pump for shipboard and trailer-mounted Fi-Fi systems. The selection process begins with the acceptance standard, followed by the design flow rate, and only then by the pump design.
Selection, supply and service from Steiner Ukraine
For a UL/FM-certified facility, the selection process begins with the list of approvals that the client or insurer must accept: if the specification requires FM 1319, the version based on NFPA 20 will not be approved. To carry out the calculation, Steiner Ukraine requires: a list of the necessary approvals, the design flow rate and pressure at the control point, the available suction head, the drive type and the requirements for the control cabinet. Based on this data, we select one of three sizes, coordinate the ‘pump–motor–controller’ package so that the approvals match, and provide a specification with certificates. Routine maintenance consists of re-packing the gland and lubricating the bearings — both operations are described in the manufacturer’s manual.
