Approval Standard

for Strainers for use with Water Spray Systems

Class Number 5551

January 1980

2002 FM Approvals LLC. All rights reserved.

Foreword

The FM Approvals certification mark is intended to verify that the products and services described will meet FM Approvals stated conditions of performance, safety and quality useful to the ends of property conservation. The purpose of Approval Standards is to present the criteria for FM Approval of various types of products and services, as guidance for FM Approvals personnel, manufacturers, users and authorities having jurisdiction.

Products submitted for certification by FM Approvals shall demonstrate that they meet the intent of the Approval Standard, and that quality control in manufacturing shall ensure a consistently uniform and reliable product. Approval Standards strive to be performance-oriented. They are intended to facilitate technological development.

For examining equipment, materials and services, Approval Standards:

a) must be useful to the ends of property conservation by preventing, limiting or not

causing damage under the conditions stated by the Approval listing; and

b) must be readily identifiable.

Continuance of Approval and listing depends on compliance with the Approval Agreement, satisfactory performance in the field, on successful re-examinations of equipment, materials, and services as appropriate, and on periodic follow-up audits of the manufacturing facility.

FM Approvals LLC reserves the right in its sole judgment to change or revise its standards, criteria, methods, or procedures.

TABLE OF CONTENTS

1.0 INTRODUCTION ................................................................................................................................................................... 1

2.0 PERFORMANCE .................................................................................................................................................................... 12.1 Sizes ................................................................................................................................................................................... 12.2 Rated Working Pressure .................................................................................................................................................... 12.3 Filter ................................................................................................................................................................................... 12.4 Flushing Outlet .................................................................................................................................................................. 12.5 Tests ................................................................................................................................................................................... 2

3.0 MARKINGS ............................................................................................................................................................................. 2

1.0 INTRODUCTIONStrainers are installed in the water supply line to water spray systems. They are used to entrap foreign materials,18 in. (3.2 mm) and larger, which may otherwise enter the system and plug the nozzles. Strainers shall be highlyreliable and durable.

FM Approval is based on examination and test of production samples, inspection of the manufacturing and/orquality control facilities, and satisfactory field experience. Particularly considered are functional suitability,adequacy of design and workmanship, uniformity and dependability of production, effectiveness of qualitycontrol, and assurance of service and of replacement parts.

Minimum physical requirements given below are guides. Mere conformity does not assure Approval, since otherconsiderations may control. Nor is strict conformity necessary; devices having different characteristics may beconsidered and Approved, if shown to be essentially equivalent or superior in performance.

2.0 PERFORMANCE

2.1 Sizes

Recognized standard sizes are: 2, 212, 3, 4, 6, 8, 10 and 12 inch (51, 64, 76, 102, 152, 203, 254 and 305 mm).

2.2 Rated Working Pressure

The body shall be designed for 175 psi (1205 kPa) rated working pressure.

2.3 Filter

2.3.1 With all perforations plugged, the filter shall have sufficient strength to resist deformation by the expectedwater pressure.

2.3.2 The filter shall be of corrosion resistant material.

2.3.3 The strainer shall be designed to permit removal of the filter for replacement or repairs without removingthe strainer from the line.

2.3.4 Friction loss through the strainer shall not exceed 10.0 psi (70 kPa) with the filter containing foreignmaterial as outlined in Test 3.

2.3.5 The filter shall be designed to entrap material 18 inch (3.2 mm) and larger.

2.4 Flushing Outlet

A flushing outlet with shut-off valve shall be provided. The outlet shall be of sufficient size to maintain a waterflow velocity of 6.0 feet (1.8 m) per second in the supply pipe when 50 psi (345 kPa) pressure is maintained atthe inlet connection to the strainer and there is no flow through the main strainer outlet. This velocity isconsidered necessary to move particles having a diameter of 12 inch (13 mm) or smaller.

January 1980 5551

FM APPROVALS 1

2.5 Tests

2.5.1 The body will be hydrostatically tested at a 700 psi (4826 kPa) pressure for five minutes. There shall beno failure as a result of this test.

2.5.2 The filter with all perforations plugged will be hydrostatically tested at 125 psi (863 kPa). There shall beno filter deformation as a result of this test.

2.5.3 Flow tests will be made to determine the friction loss with the strainer retaining foreign material equal involume to that of 212 feet (0.8 m) of the supply pipe for which the strainer is designed. The foreignmaterial shall be composed of screened gravel which will pass through a screen having 1116 inch (17 mm)square openings but will be retained on a screen having 716 inch (11 mm) square openings. Test flows shallbe as follows:

Strainer Sizein. (mm)

Flow(gpm)

2 (51) 180212 (64) 2503 (76) 380

4 (102) 6606 (152) 15008 (203) 2700

10 (254) 420012 (305) 6000

2.5.4 Flow tests will be made through the flushing outlet to determine that at 50 psi (345 kPa) pressure on theinlet, the velocity through the supply pipe is not less than 6.0 feet (1.8 m) per second.

3.0 MARKINGSStrainers shall be plainly marked with the name or trademark of the manufacturer, size, rated working pressure,and an arrow showing the flow direction.

5551 January 1980

2 FM APPROVALS

1.0 INTRODUCTION 2.0 PERFORMANCE 2.1 Sizes 2.2 Rated Working Pressure 2.3 Filter 2.4 Flushing Outlet 2.5 Tests

3.0 MARKINGS