BS 750-1984 - Specification for Underground Fire Hydrants & Surface Box Frames & Covers.pdf

8/10/2019 BS 750-1984 - Specification for Underground Fire Hydrants & Surface Box Frames & Covers.pdf

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BRITISH STANDARD BS 750:1984IncorporatingAmendment Nos. 1, 2and 3 andCorrigendum No. 1

Specification forunderground fire

hydrants and surface

box frames and covers

ICS 13.220.10

opyright British Standards Institutioneproduced by IHS under license with BSI - Uncontrolled Copy

Not for Resaleo reproduction or networking permitted without license from IHS

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BS 750:1984

This British Standard, havingbeen prepared under thedirection of the FireStandards Committee, waspublished under the authorityof the Board of BSI and comesinto effect on 31 January 1984

BSI 24 August 2005

First published August 1937

First revision January 1950

Second revision August 1964

Third revision February 1977

Fourth revision January 1984

ISBN 0 580 13552 7

Committees responsible for thisBritish Standard

The preparation of this British Standard was entrusted by the Fire StandardsCommittee (FSM/-) to Technical Committee FSM/8 upon which the following

bodies were represented:

British Fire Services Association

British Plastics Federation

British Valve Manufacturers Association Ltd.

Chief and Assistant Chief Fire Officers Association

Department of the Environment (Property Services Agency)

Fire Extinguishing Trades Association

Greater London Council

Home Office

Institution of Fire EngineersMinistry of Defence

National Water Council

Amendments issued since publication

Amd. No. Date Comments

7658 June 1993

10434 April 1999

14520 8 July 2004

15667Corrigendum

24 August 2005 Correction to Amendment No. 1 affectingClause 9, D.4.3.4, Figure 6and Figure 7

Indicated by a sideline in the margin



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BS 750:1984

BSI 24 August 2005 i

ContentsPage

Committees responsible Inside front cover

Foreword ii

Section 1. General

1 Scope 1

Section 2. Fire hydrants

2 Classification and design 3

3 Wedge gate (type 1) 3

4 Screw-down (type 2) 5

5 General requirements 6

6 Type requirements 8

7 Production requirements 10

8 Hydrostatic test certificate 10

9 Marking 10

Section 3. Surface box frames and covers

10 Grading 1111 Materials 11

12 Manufacture, workmanship and coating 11

13 Design features 12

14 Marking 13

15 Type requirements 14

16 Production requirements 15

17 Test certificate 15

Appendix A Information to be supplied by the purchaser 16

Appendix B Inspection of manufacture 16

Appendix C Type and production hydrostatic tests for screwed outlets 16

Appendix D Type tests for strength, security and endurance 17

Appendix E Type and production loading tests for surface box frames andcovers 21

Figure 1 Example of fire hydrant wedge gate (type 1) showing requireddimensions 4

Figure 2 Example of fire hydrant screw-down (type 2) showing requireddimensions 5

Figure 3 Screwed outlet (round thread) and outlet cap showing requireddimensions 7

Figure 4 Minimum bedding width of surface box frame showing requireddimensions 12

Figure 5 Detail of keyhole and key 14Figure 6 Impact test apparatus 19

Figure 7 Load/deflection test apparatus 20

Table 1 Deleted

Table 2 Deleted

Table 3 Deleted

Table 4 Deleted

Table 5 Deleted

Table 6 Deleted

Table 7 Deleted

Table 8 Deleted

Table 9 Deleted

Table 10 Production test load requirements and acceptance criteria 15

Publications referred to 23



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BS 750:1984

ii BSI 24 August 2005

Foreword

This British Standard has been prepared under the direction of the FireStandards Committee and is a revision of BS 750:1977 which is withdrawn.

In this revision the opportunity has been taken of introducing type tests for

plastics screwed outlets and additional grades of metals for certain components.In addition spindle sealing for screw-down type hydrants is now specified. Flangerequirements have also been revised.

Surface box frames and covers with modified test procedures are specified ingreater detail in this edition.

Appendix AandAppendix Bdo not contain requirements of this standard and areincorporated for guidance only.Appendix C,Appendix DandAppendix Edo formpart of the requirements of the standard.

BS 5306-1 contains recommendations for the planning, installation, testing andmaintenance of underground fire hydrants.

It has been assumed in the drafting of this British Standard that the execution ofits provisions is entrusted to appropriately qualified and experienced people, for

whose guidance it has been prepared.

This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application.

Compliance with a British Standard does not of itself confer immunityfrom legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii,pages 1 to 23 and a back cover.

The BSI copyright notice displayed in this document indicates when thedocument was last issued.

Sidelining in this document indicates the most recent changes by amendment.



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BS 750:1984

BSI 24 August 2005 1

Section 1. General

1 Scope

This British Standard specifies the operational and safety requirements for underground fire hydrantsconforming to BS EN 1074-6. It includes hydrants with valves of the wedge gate type and the screw-downtype suitable for a maximum allowable operating pressure (PFA) of 1.6 MPa1)and 2.5 MPa. It also specifiesrequirements for their surface box frames and covers.

NOTE 1 The titles of the publications referred to in this standard are listed on page 23.

NOTE 2 PFA is defined in BS EN 805.

1) 1 MPa = 10 bar.



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2 blankopyright British Standards Institutioneproduced by IHS under license with BSI - Uncontrolled Copy


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BS 750:1984


Section 2. Fire hydrants

2 Classification and design

Hydrants shall have a design life of 50 years. This shall be determined by reference to the materials usedin the construction, their properties, the engineering design of the hydrant, the normal situation ofinstallation and conditions of use. The manufacturer shall demonstrate compliance with this requirementby reference to the materials of construction being in accordance with standards contained herein. Wherematerials have time-dependent properties these shall be selected with reference to the manufacturers dataon such properties to determine their suitability for the function and lifespan.

Where elements of the hydrant are designed to be serviceable, this shall not be regarded as reason to designfor a shorter operating life. Serviceable components shall include those having potential for accidentaldamage and wear from abnormal use. The manufacturer shall ensure that parts that are considered to besubject to wear shall be available for the lifetime of the valve.

Hydrants shall be one of the following two types:

type 1 wedge gate (see Clause 3and Figure 1);

type 2 screw-down (see Clause 4and Figure 2).

Screw-down hydrants of type 2 shall conform to one of the following patterns.

a) Type 2a: The bonnets and/or outlets of this pattern shall be secured in such a manner that they cannotbe removed when installed in a pipeline. With the exception of stem sealings, it shall be made clear inthe manufacturers literature that the hydrant cannot be maintained whilst in situ.

b) Type 2b: Designed to facilitate maintenance of obturator, stem, outlet and their seals, in situ, whilstmounted in a chamber having a surface box frame and cover conforming to Section 3. They shall have:

1) Y and Z flanges DN 50, PN 16 or PN 25 compatible with the mating dimensions given inBS EN 1092-2 and BS EN 1092-3 as appropriate, and using bolts, studs or set screws specified(i.e. M16). They need not be circular and are not required to have raised faces.

NOTE Y or Z flanges may have a groove in the face to accommodate an O ring. The bolt holes may be slotted and the slotsmay extend to the periphery of the flange.

2) A bolted connection at the body/bonnet joint with a minimum of three bolts.

c) Type 2c: Designed to facilitate maintenance as type 2b. They shall have bolted connections betweenboth the outlet and body and the bonnet and body. These connections shall each have a minimum of threebolts.

d) Type 2d: Designed to facilitate maintenance as type 2b, but having means of connection of the outletand/or bonnet to the hydrant body other than type 2c (see 5.2.4and 5.9).

Type 2b, type 2c and type 2d hydrants shall be capable of being dismantled in situ using standard, readilyavailable tools.

3 Wedge gate (type 1)

3.1 Hydrants of the wedge gate type shall conform to the dimensions shown in Figure 1.

3.2 The wedge gate valve shall conform to the recommendations and requirements of BS 5163-1,BS 5163-2, BS EN 1074-1 and BS EN 1074-2 for PN 16 or PN 25 valves (see also 5.4).

3.3 Materials for duckfoot bends shall conform to BS EN 545.

Table 1Deleted



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BS 750:1984

4 BSI 24 August 2005

Section 2

All dimensions are in millimetres

Key

1 Stem cap 4 Wedge gate valve

2 Outlet cap (for details see Figure 3) 5 65 nominal bore

3 Outlet (for details see Figure 3) 6 Duckfoot bend

Figure 1 Example of fire hydrant wedge gate (type 1) showing required dimensions

2

3

4

6

DN8

0

1

5

300

XXX

Y

Z



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BS 750:1984


Section 2

4 Screw-down (type 2)

4.1 Hydrants of the screw-down type shall conform to the dimensions shown in Figure 2.

The clearance between the back of flange X and the body shall be not less than 17 mm at the position ofany bolt hole.

4.2 Materials for the bodies of screw-down type hydrants shall conform to BS EN 1503-3.

Table 2Deleted

4.3 Hydrants shall be fitted with either captive or loose valves, which shall be faced with a resilientmaterial in accordance with BS EN 681-1 type WA (for cold potable water).

Table 3Deleted


Key

1 Stem cap 3 Outlet (for details see Figure 3)

2 Outlet cap (for details see Figure 3) 4 65 nominal bore

Figure 2 Example of fire hydrant screw-down (type 2) showing required dimensions

2

DN 80

1

Y

100

3

4

Z

X



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BS 750:1984


Section 2

4.4 For screw-down type hydrants, copper alloy materials for the body seatings, if fitted, and for thethreaded part of the valve which engages with the stem shall conform to BS EN 1982.

NOTE 1 It is not essential for a body seating to be fitted to ensure a good seal. Polymeric coatings may be used instead provided thatthe performance requirements of Clauses 6and 7.

NOTE 2 For the threaded part of the valve, copper alloy materials normally used are gunmetal, high-tensile brass, aluminiumbronze and die-cast brass.

Table 4Deleted

4.5 Stems of screw-down type hydrants shall be manufactured from either:

a) copper alloys conforming to BS EN 1982; or

b) stainless steel conforming to BS EN 10088-1 with a minimum chromium content of 13 %.

4.6 Stem sealings shall be of one of the following three types:

a) stuffing box and gland type;

b) toroidal sealing ring (O ring) type;c) other pressure actuated types of seal.

The valve shall be capable of stem seal changing while the valve is under pressure and fully closed.

Where stem sealing is of the toroidal sealing ring (O ring) type then two such seals shall be used.

Table 5Deleted

Where stem sealing is of the toroidal sealing ring (O ring) type or other pressure actuated type then awiper ring shall be positioned above the seals to prevent the ingress of foreign matter.

4.7Deleted

5 General requirements

5.1 Inlet flanges

The mating dimensions of flange X shown in Figure 1and Figure 2shall be in accordance withBS EN 1092-2, DN 80 and PN 16 or PN 25.

NOTE It need not be circular or full form and may be provided with additional holes, which may be slotted, to suit other flangedesigns.

5.2 Screwed outlets

5.2.1 The screwed outlet shall be manufactured from either copper alloy conforming to BS EN 1982 orplastics and shall conform to 6.4and 6.5. The outlet shall conform to the dimensions shown in Figure 3.

The screwed outlet shall be provided with a cap to cover the outlet thread (see Figure 3). It shall be securelyattached to the hydrant by a chain or other flexible device.

Table 6Deleted5.2.2 The screwed outlet shall be provided with a cap to cover the outlet thread (see Figure 3). It shall besecurely attached to the hydrant by a chain or other flexible device.

5.2.3 The design of hydrant and outlet shall permit full engagement onto the outlet of a standpipeconforming to BS 336:1989, Figure 12.

5.2.4 Outlets connected by means other than that described for type 2b and type 2c shall be secured by twoindependent and functionally different means. These different means shall each be capable of preventingthe outlet becoming unintentionally detached in the absence of the other.

Outlets connected by means other than that described for type 2b and type 2c shall conform to the typerequirements in Clause 6with:

both security systems in place;

only one of the security systems in place;

only the other security system in place.



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BS 750:1984


Section 2


Key

1 Outlet cap 5 Outlet to be screwed with round thread, two threads per 25.4 mm crest diameter

82.2 mm, root diameterk68 mm2 Cap not to be threaded

3 Feather edge to be removed t Thickness of thread 5.7 mm4 Taper (see Note 2)

NOTE 1 The details of female round threads for stand-pipes are given in BS 336.

NOTE 2 Deviations from a uniform taper are permitted.

Figure 3 Screwed outlet (round thread) and outlet cap showing required dimensions

2

1

3

4

40

5

30

70

65

54

0.8

R2.85R3.5

7.2

t

2 t.p.i12.7

00.4

00.4



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BS 750:1984


Section 2

5.3Deleted

Table 7Deleted

5.4 Stem caps

5.4.1 The stem shall be provided with a cast iron cap conforming to BS 5163-2.

The cap shall be securely fixed to the stem so that it remains fixed in position during normal use. Themeans of fixing shall be such as to permit removal of the cap by authorized users but to prevent, as far asis practicable, unauthorized removal.

NOTE 1 The design of the stem cap recess should suit the stem end of the valve.

NOTE 2 Hydrant key details are included in BS 336.

5.4.2Valves shall be closed by turning the stem in a clockwise direction when viewed from above.

5.5 Drain plug or frost valve

Each screw-down type hydrant and each duckfoot bend on a wedge gate type hydrant shall be provided witha drain boss on the outlet side. It shall be located at the lowest practicable point which will permit thefitting of a blank plug, drilled drip plug or self operating frost valve.

5.6 Workmanship

Corresponding parts of hydrants of the same design and manufacture shall be interchangeable.

5.7 Coating

All cast iron parts shall be thoroughly cleaned and, before rusting commences, shall be coated.

5.8 Maintenance of water purity (potable water systems only)

All non-metallic materials used including coatings and lubricants shall be in accordance with BS 6920-1.

5.9 Bonnets

Bonnets connected by means other than that described for type 2b and type 2c shall be secured by twoindependent and functionally different means. These different means shall each be capable of preventingthe bonnet becoming unintentionally detached in the absence of the other.

Bonnets connected by means other than that described for type 2b and type 2c shall conform to the typerequirements in Clause 6with:

both security systems in place;

only one of the security systems in place;

only the other security system in place.

6 Type requirements

6.1 GeneralA single set of tests only is required to ascertain that the hydrant design meets the stated requirements ofthe relevant part of this standard and BS EN 1074-1, BS EN 1074-2 and BS EN 1074-6.

NOTE Requirements for testing individual production units are given in Clause 7.

6.2 Overall flow

When fitted with a standard round thread outlet as shown in Figure 3, the hydrant shall deliver not lessthan 2 000 L/min at a constant pressure of 0.17 MPa at the inlet to the hydrant.

6.3 Hydrostatic pressure

Text deleted

The hydrant assembly shall be pressure tested in accordance with BS EN 1074-6.

6.4 Impact strength requirements of screwed outlets

Five sample outlets shall be subjected to the test method of D.1during which none shall suffer suchdamage as to prevent a stand-pipe being attached.



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BS 750:1984


Section 2

Following this test the sample outlets shall be attached to a hydrant and tested in accordance withAppendix Cwith no visible signs of leakage.

6.5 Load/deflection requirements of screwed outlets

Ten sample outlets shall be subjected to the test method of D.2. The five samples when subjected to theprocedure of D.2.3.1shall have exhibited a maximum angular deflection of not greater than 7.5and shallhave a residual angle of deflection of not greater than 2, both measured from the unloaded datum position.

The samples, in addition, shall exhibit no fractures and shall not have suffered damage so as to preventsubsequent reconnection of the standpipe.

The remaining five samples when subjected to the test method of D.2.3.2shall exhibit no leakage duringthe test.

6.6 Strength and leak-tightness requirements of screwed outlets: Resistance of screwed outletsto rotational force

When tested in accordance with D.3the following shall apply.

There shall be no visually detectable movement of the outlet occurring during the application of theinitial (50 2.5) Nm torque in either direction.

Outlets shall withstand a torque of (300 15) Nm applied in both clockwise and anticlockwise directionsfor a minimum of 30 s whilst subjected to the pressures specified. There shall be no visible signs of leakageat the outlet/body joint for the duration of the test. There shall be no damage which would impairsubsequent performance of the hydrant or connection of a standpipe. The rotational movement during theapplication of the (300 15) Nm torque shall not exceed 10.

Leakage, at the outlet/body joint, when testing with only one of the security systems shall not be deemed afailure.

6.7 Resistance of hydrants to operating forces

This test shall be carried out prior to the tests described in 6.8and 6.9.

Hydrants, whilst subjected to a minimum hydraulic pressure of (PFA + 0.4) MPa, shall withstand in thefully open and in the fully closed positions a torque of (210 10) Nm applied simultaneously with a lateralforce giving a bending moment of (500 25) Nm at the top of the stem and there shall be no visible signsof leakage over a period not less than 1 min.

NOTE The outlet should be capped when testing is carried out in the fully open position.

6.8 Strength and leak-tightness requirements of type 2a and type 2d bonnets: Resistance ofbonnets to rotational force

When tested in accordance with D.4the following shall apply.

The connection between the hydrant body and bonnet of type 2a and type 2d pattern hydrants shallwithstand a torque of (300 15) Nm applied to the bonnet in both clockwise and anticlockwise directionsfor a minimum of 30 s.

There shall be no visible signs of leakage during the test and there shall be no dislodgement or damage toeither body or bonnet or the method of securing the bonnet to the body which would impair subsequentperformance of the hydrant.

There shall be no visually detectable rotational movement of the bonnet occurring during the applicationof the initial (50 2.5) Nm torque in either direction.

The total rotational movement during the application of the (300 3) Nm torque shall not exceed 10.

Leakage, at the bonnet/body joint, when testing with only one of the security systems shall not be deemeda failure.

6.9 Endurance of the hydrant and outlet

6.9.1 Endurance of complete hydrant

Hydrants shall conform to BS EN 1074-6.



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BS 750:1984


Section 2

6.9.2 Endurance of outlets

Mount the outlet to a hydrant. Fit a standpipe or blanking cap in accordance with BS 336 to the outlet with

a torque of (150 7.5) Nm and then remove it.

Repeat this procedure 200 times before testing in accordance withAppendix Cwhen there shall be no signsof leakage from the outlet.

7 Production requirements

7.1 Hydrant assembly: Resistance to internal pressure of the shell and of all pressurecontaining components and resistance of the obturator to differential pressure

Each hydrant assembly shall be tested in accordance with and conform to BS EN 1074-6.

7.2Deleted

7.3 Screwed outlets

Each screwed outlet shall be tested in accordance with the method ofAppendix C. If the screwed outlet issupplied attached to the hydrant then it shall be tested either integrally with it or after removal from thehydrant. There shall be no visible sign of leakage from the screwed outlet.

8 Hydrostatic test certificate

Where requested a certificate shall be made available which certifies that the hydrant conformsto Clause 7.

9 Marking

Each hydrant assembly shall be clearly marked, either integrally with the stated components or on a plateof durable material securely fixed to that component in accordance with BS EN 1074-6 and the following:

a) the number and date of this British Standard, i.e. BS 750:19842);

b) the type designation, i.e. 1, 2a, 2b, 2c or 2d;

c) if loose valve mark LV or Loose;

d) an identification number (the reference used by the manufacturer allowing identification).

2) Marking BS 750:1984 on or in relation to a product is a claim by the manufacturer that the product has been manufactured inaccordance with the requirements of the standard. The accuracy of such a claim is therefore solely the manufacturersresponsibility. Enquiries as to the availability of third party certification to support such claims should be addressed to theDirector, Quality Assurance Division, British Standards Institution, Maylands Avenue, Hemel Hempstead, Herts HP2 4SQ inthe case of certification marks administered by BSI or to the appropriate authority for other certification marks.



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BS 750:1984


Section 3. Surface box frames and covers

10 Grading

Surface box frames and covers shall be graded as follows:3)4)

11 Materials

Materials for the manufacture of surface box frames and covers shall be chosen from those givenin BS EN 1561 for grey cast iron or BS EN 1563 for spheroidal graphite cast iron.

Table 8Deleted

12 Manufacture, workmanship and coating

12.1 Manufacture and workmanship

All cast units shall be cleanly cast and shall be free from air holes, sand holes, cold shuts and chill. Theyshall be neatly dressed and carefully fettled. All castings shall be free from voids, whether due to shrinkage,gas inclusions or other causes.

12.2 Coatings

All units shall be supplied as follows:

a) uncoated; or

b) units shall be thoroughly cleaned and dried before being given a short term coating of one of thefollowing:

1) hot applied coal tar coating material conforming to BS 4164, type 1 or type 2 materials; or

2) cold applied black bitumen solution conforming to BS 3416, type 1 or type 2 material, except thatother solvents to accelerate the drying properties of the coating may be substituted;

or

3) hot applied bitumen based coating material conforming to and applied in accordance with BS 4147for type 1, grade C material.

The choice of material and method of coating in respect of 1), 2) and 3) above, shall be at the option ofthe manufacturer.

NOTE Units are normally supplied in the coated state unless otherwise specified by the purchaser.

3) The magnitude of the stated wheel load is as exerted by a stationary vehicle.4) As authorized by Statutory Instrument SI.1101 of 1973 of the Motor Vehicles (Authorization of Special Types) GeneralOrder 1973.

Grade A. Capable of being used in carriageways and other areas carrying fast-movingnormal commercial vehicles with wheel loads3)up to 5 tonnes and slow-movingspecially authorized4)vehicles with wheel loads up to 11.5 tonnes.

Grade B. Capable of bearing wheel loads3)up to 5 tonnes for use in areas to which vehicleswould have only occasional access, including areas such as footpaths and verges.



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BS 750:1984


Section 3

13 Design features

13.1 Clear opening

The minimum clear opening in surface box frames shall be as follows:

a) for wedge gate (type 1) hydrant: 215 mm 495 mm;

b) for screw-down (type 2) hydrant: 230 mm 380 mm.

Projections at corners, required for manufacturing purpose, shall not give a resultant reduction ofminimum clear opening area in excess of 1 600 mm2at each of the corners.

13.2 Frame depth and width

The depth of the frame shall be not less than 100 mm for grade A and 75 mm for grade B. The minimumbedding width of the frame shall be 50 mm (see Figure 4).

13.3 Fit of frames and covers

Surface box frames and covers shall be designed so that the top of the cover is flush with the top of theframe. Grade A covers and frames shall incorporate a permanent non-rock design feature.

13.4 Registers

Where the directional installation of the cover relative to the frame is an essential feature of a non-rock

design, a register shall be provided.

All dimensions are in millimetres.

Key

1 Surface box frame

2 Surface box cover

3 Bedding width

Figure 4 Minimum bedding width of surface box frame showing required dimensions

21

3

50



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BS 750:1984


Section 3

13.5 Drainage and skid resistance

Covers of solid-top type shall be self-draining and have a raised pattern, such as chequers, so as to provide

a skid-resisting surface.

13.6 Clearance

The average of all clearances between cover section and frame, and between section and section, shall notexceed 3 mm.

13.7 Surface box cover lifting arrangement

13.7.1 General

13.7.1.1 Each section (element) of a cover shall be provided with at least one prising slot at the midpoint ofone of the short edges of the cover, and at least one keyhole.

13.7.1.2A single section (element) cover which does not conform to 13.4shall be provided with two prisingbar recesses at the midpoints of the two short edges, and two keyholes.

13.7.2Keyholes

Keyholes shall conform to the dimensions shown in Figure 5a).

13.7.3Prising bar recesses

Prising bar recesses shall have a nominal length of 35 mm and a nominal width of 10 mm. Grade A coversshall be formed with a lip not more than 15 mm from the top, not less than 5 mm deep and running the fulllength of the recess.

13.7.4Additional requirements

Lifting keys, if provided, shall conform to the dimensions shown in Figure 5b).

NOTE 1 See c) 3) ofAppendix A.

NOTE 2 Attention is drawn to the Manual Handling Regulations. Fire hydrants are frequently operated in emergency situations bya single fire-fighter. This necessitates that one person should be able to readily lift the cover with a prising bar and then clear withease the minimum clear opening dimensions as given in 13.1. The design of the fire hydrant with cover should present minimalopportunity for the cover to drop into the chamber.

13.8 Coupling of multiple sections

Where covers are made up of two sections, the sections shall be loosely coupled and fasteners provided withmeans to prevent the tightening together of the cover sections. Fastening shall be of steel or spheroidalgraphite cast iron and shall have a cross section of not less than 100 mm2(equivalent to M12 bolting).

14 Marking

Surface box covers shall be clearly marked by having the words FIRE HYDRANT in letters not lessthan 30 mm high, or the initials F.H. in letters not less than 75 mm high, cast into the cover.

The cover and frame shall have clearly cast thereon the number and date of this British Standard and theappropriate grade as given in Clause 10, e.g. BS 750:19845)grade A.

Text deleted

5) See asterisked footnote toClause 9a).



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BS 750:1984


Section 3

15 Type requirements

Surface box frames and covers, whether made of grey cast iron or spheroidal graphite cast iron, shall becapable of supporting without fracture the design loads of 300 kN for grade A and 125 kN for grade B whentested in accordance withAppendix E.

Table 9Deleted


a) Keyhole b) Key

Key

1 Open

2 Plan

3 Line of raised pattern

4 Alternative shape

Minimum Maximum D 20 1

A 22 25 E 15 1

B 9 13 F 6 1

C 44 G 40 1

Figure 5 Detail of keyhole and key

2

1

C

BAAA

A - A

3

4

E

G F

D



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BS 750:1984


Section 3

16 Production requirements

Samples from lots of surface box frames and covers, when tested in accordance withAppendix E, shall be

capable of supporting the design loads shown in Table 10and shall conform to the acceptance criteria inthe same table.

Table 10 Production test load requirements and acceptance criteria

Acceptance of lots of frames and covers shall be in accordance with BS 6001, QL 2.5 % inspection level II(Normal Inspection). The acceptance of a lot of frames and covers by the purchaser shall not prejudice hisright to reject the lot if it is subsequently found not to meet the requirements of this clause.

17 Test certificate

Provision shall be made for a certificate to be made available which certifies that samples from eachproduction lot from which the delivery is made up conform to the requirements of Clause 16.

Material Grade of frame

and cover

Production test load Acceptance criteria

kN

Grey cast iron (CI) A 300

No fractureB 125

Spheroidal graphite cast iron(SG)

A 200

No fracture or any permanentsetagreater than 0.2 % of thedistance between selectedseatings

B 85

a Measured at the mid-point between any two selected supporting seatings after removal of the test load.



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BS 750:1984


Appendix AInformation to be supplied by the purchaser

The purchaser should supply the manufacturer with the following information at the time of the enquiry.

a) Information on options which are detailed in this standard, common to both wedge gate andscrew-down type hydrants:

1) whether a wedge gate (type 1) or screw-down (type 2a, 2b, 2c or 2d) is required (see Clause 2);

2) form of stem sealing required (see 4.6);

3) outlet material, whether copper alloy or plastics (see 5.2);

4) whether a blank plug, drilled drip plug or self-operating frost valve is required (see 5.5);

5) if a certificate of test is required (see Clause 8);

6) if a surface box is to be supplied (see Section 3).

b) Suggested additional information common to both wedge gate and screw-down type hydrants:

1) whether valves are for use in or transport through the tropics;

2) whether for sea water or other non-potable water use;

3) special provisions for despatch;

4) need for any special coatings;

5) type of securing stem of stem cap (see 5.4for guidance);

6) whether witnessing of tests is desired (seeAppendix B).

c) Information specific to surface box frames and covers:

1) whether grade A or grade B design (see Clause 10);

2) whether for wedge gate or screw-down type hydrant (see 13.1);3) whether lifting key(s) are required (see 13.7.4);

4) whether valve opening direction is required to be marked (see Clause 14); if so, the direction ofopening;

5) if a certificate of test is required (see Clause 17).

Appendix BInspection of manufacture

It is recommended that the purchaser or his authorized representative should be given all reasonablefacilities for inspection.

Should the purchaser wish to witness production tests (see Clauses 7and 16) made to his purchase orderhe should inform the manufacturer accordingly and the latter should give reasonable notice of the date ordates on which the tests will be carried out.

Appendix CType and production hydrostatic tests for screwed outlets

Text deleted

Blank off the screwed outlet using a blank cap and connect the other end to a pressurized water supply.Subject the screwed outlet to a hydraulic pressure of not less than 1.5 times PFA for a period of not lessthan 1 min.

NOTE The test may be carried out in conjunction with the tests on the hydrant (see Clauses 6and 7).



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Appendix DType tests for strength, security and endurance

D.1 Impact strength test for screwed outlets

D.1.1Apparatus

A specimen outlet, or in the case of type 2a and type 2d, a specimen hydrant is mounted on a rigid plate sothat the centre line of the flow path through the outlet is horizontally orientated. Mounted above thespecimen is a guide tube of suitable length and diameter to guide but not restrain the passage of a 10 kgweight. The lower end of the weight has a hardened steel nose projecting for 50 mm and terminating in ahemisphere of 10 mm radius. The guide tube is positioned as shown in Figure 6such that thehemispherical striker bridges the two threads furthermost from the flange at a circumferential position ofbetween 30and 90from the end of the thread. The guide tube enables the 10 kg weight to be secured insuch a way that the hemispherical striker is held at the height specified in the procedure in D.1.3.

NOTE The guide tube supports may need to be adjustable.

D.1.2 Test specimens

Five randomly selected outlets, in the condition that they are supplied to the user, shall be tested. Theyshall be free from voids and other visible defects.

D.1.3Procedure

Mount the sample in the position as described above. Set the hemispherical striker at a height of 450 mmabove the point of impact and then allow it to fall.

D.2 Load/deflection test

D.2.1Apparatus

The specimen outlet or, in the case of type 2a and type 2d a specimen hydrant is mounted to a rigid plate

having a facility to enable an internal water pressure of (PFA + 0.4) MPa to be applied. Either

a standpipe of sufficient length or a blanking cap modified to have a suitable loading bar is connected to

the test outlet. The standpipe or loading bar shall be of sufficient length that the specified bending moment

can be generated by a force applied at a minimum distance of 900 mm from the mounting point of the outlet

under test. The test arrangement is shown in Figure 7. The force (F) is applied in a vertical plane in either

an upward or downward direction. The force is such as to produce a minimum bending moment of 1 000 Nm

for the test procedure described in D.2.3.1and for the test procedure of D.2.3.2a minimum bending

moment of 500 Nm together with a hydrostatic pressure of (PFA + 0.4) MPa.


Ten specimen outlets or, in the case of type 2a and type 2d, 10 specimen hydrants, in the condition thatthey are supplied to the user are randomly selected. Five samples shall be used for the first part of theprocedure (see D.2.3.1) and five for the second (see D.2.3.2).

D.2.3Procedure

D.2.3.1Apply a minimum bending moment of 1 000 Nm, as described in D.2.1, for a period of 10 s. Notethe angular deflection at this point. Remove the applied force and after 2 min measure the residual angulardeflection.

D.2.3.2 With a hydrostatic pressure of (PFA + 0.4) MPa applied within the outlet apply a minimumbending moment of 500 Nm, as described in D.2.1, for a period of 1 min during which time check for leaks.At the end of this period remove the applied force and hydrostatic pressure.

D.2.3.3 Repeat the test procedure D.2.3.1and D.2.3.2three times with the force applied at approximately(a) 45, (b) 90and (c) 180from the position of the first test.

D.2.3.4 Repeat the test procedure D.2.3.3in the most potentially vulnerable orientation of the outlet to theforce, unless this position has already been covered by the tests in D.2.3.1, D.2.3.2and D.2.3.3.

+0.1

0

+0.10

+0.10



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D.3 Test for rotational resistance of outlet

D.3.1Apparatus

A suitable test rig capable of withstanding test forces shall be provided to mount the hydrant.


One randomly selected hydrant, in the delivery condition shall be tested.

D.3.3Procedure

D.3.3.1 Mount and secure the hydrant by its inlet flange, to the test rig. Fit a blanking cap to the outletand if necessary provide a means of rigidly securing it to the threaded portion of the outlet to prevent thecap being removed during the anticlockwise test.

D.3.3.2Apply a torque of (50 2.5) Nm directly to the outlet in a clockwise direction and hold forminimum 30 s and observe for any visual movement. Repeat the test in an anticlockwise direction andobserve for any visual movement.

D.3.3.3 Repeat D.3.3.2with a torque of (300 15) Nm and measure the total angular movement of theoutlet.

D.3.3.4 Repeat D.3.3.3with an internal hydrostatic pressure of (PFA + 0.4) MPa. Examine theoutlet/body joint during the test for visible signs of leakage.

D.4 Test for rotational resistance of bonnets

D.4.1Apparatus

A suitable test rig capable of withstanding test forces shall be provided to mount the hydrant.


One randomly selected hydrant, in its delivery condition, shall be tested.

D.4.3Procedure

D.4.3.1 Mount the hydrant on the test rig and fit a blanking cap to the outlet. Provide a means of applyinga torque either directly to the bonnet or by means of any suitable device which shall not add to the strengthof the body/bonnet connecting system.

D.4.3.2Apply a torque of (50 2.5) Nm directly to the bonnet in a clockwise direction and hold for aminimum of 30 s and observe for any visual movement. Repeat the test in an anticlockwise direction andobserve for any visual movement.

D.4.3.3 Repeat D.4.3.2with a torque of (300 15) Nm and measure the total angular movement of theoutlet.

D.4.3.4 Repeat D.4.3.3with an internal hydraulic pressure of (PFA + 0.4) MPa. Examine thebonnet/body joint during the test for visible signs of leakage.

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Key

1 Guide tube supports 7 Joint

2 Weight 8 End of guide tube positioned at such a height that theweight does not leave the tube

3 Guide tube

4 R 10 hemispherical end on weight 9 Outlet

5 Path of weight 10 End of thread

6 Hydrant or outlet mounted as described in D.1.1 11 Rigid support plate for hydrant and guide tube

Figure 6 Impact test apparatus



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Key

1 Rigid support plate for outlet 5 Hole in plate to enable test pressure to be applied to outlet

2 Outlet 6 Blanking cap and washer or standpipe

3 Force applied (see 6.5) 7 Loading bar or standpipe

4 Joint 8 Rigid support plate for hydrant

Figure 7 Load/deflection test apparatus

900



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Appendix EType and production loading tests for surface box frames and covers

E.1 Apparatus

E.1.1 Standard frameto be used as a supporting frame.

E.1.2Bearing blockof 300 mm 200 mm, of hardwood faced with hard rubber or other resilient material,and sufficiently rigid to ensure that the load on the cover is evenly distributed over the full area of the block.

E.1.3Device, preferably a hydraulic testing machine, for applying the load. The device shall be capable ofapplying a load at least 25 % greater than 300 kN for grade A and 125 kN for grade B. If a testing machineis used it shall conform to the accuracy requirements for grade A or grade B testing machines given inBS 1610. If any other load-measuring device is used it shall be accurate to within 2 % of the indicated load.

E.1.4 Measuring device, accurate to 0.1 mm, suitable for indicating deflection measurements on spheroidalgraphite cast iron units.

E.2 Type test (grey cast iron and spheroidal graphite cast iron frames and covers)

Support the cover in the frame (E.1.1) and position the bearing block (E.1.2) centrally on and wholly withinthe perimeter of the unit or section(s) being tested. Apply a test load of 300 kN for grade A and 125 kN forgrade B without shock, and sustain it for a minimum of 30 s.

E.3 Production batch test

E.3.1 Grey cast iron frames and covers

Support the cover in the frame (E.1.1) and position the bearing block (E.1.2) centrally on and wholly withinthe perimeter of the unit or section(s) being tested. Apply the appropriate test load indicated in Table 10,without shock, and sustain it for a minimum of 30 s.

E.3.2 Spheroidal graphite cast iron frames and covers

Support the cover in the frame (E.1.1) and position the bearing block (E.1.2) centrally on and wholly withinthe perimeter of the unit or section(s) being tested. Before the load is applied take an initial reading withthe measuring device (E.1.4) at a point midway between two selected supporting seatings to establish adatum point. Where it is not practicable to make this measurement exactly on the line drawn between thetwo supporting seatings it shall be taken on a line parallel to, and as near as possible to, this line.

Apply the appropriate test load indicated in Table 10, without shock, five times, sustaining alternatingmaximum and zero loads for minimum periods of 20 s; then take a second reading at the datum point.Record the difference between the two readings as the permanent set.



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Publications referred to

BS 336, Specification for fire hose couplings and ancillary equipment.

References deleted

BS 1610, Methods for the load verification of testing machines.

References deleted

BS 3416, Specification for black bitumen-based coating solutions for cold application, suitable for use incontact with potable water.

References deleted

BS 4147, Specification for bitumen based hot applied coating material for protecting iron and steelincluding a suitable primer.

BS 4164, Specification for coal-tar-based hot-applied coating materials for protecting iron and steelincluding suitable primers where required.

References deleted

BS 5163-1, Valves for waterworks purposes Part 1: Predominantly key-operated cast iron gate valves

Code for practice.6)

BS 5163-2, Valves for waterworks purposes Part 2: Stem caps for use on isolating valves and associatedwater control apparatus Specification.6)

BS 5306-1, Fire extinguishing installations and equipment on premises Part 1: Hydrant systems, hosereels and foam inlets.

BS 6001 (all parts), Sampling procedures and tables for inspection by attributes.

BS 6920-1, Suitability of non-metallic products for use in contact with water intended for humanconsumption with regard to their effect on the quality of the water Part 1: Specification.

References deleted

BS EN 545, Ductile iron pipes, fittings, accessories and their joints for water pipelines Requirements andtest methods.

BS EN 681-1, Elastomeric seals Material requirements for pipe joint seals used in water and drainageapplications Part 1: Vulcanized rubber.

BS EN 805, Water supply Requirements for systems and components outside buildings.

BS EN 1074-1, Valves for water supply Fitness for purpose requirements and appropriate verificationtests Part 1: General requirements.

BS EN 1074-2, Valves for water supply Fitness for purpose requirements and appropriate verificationtests Part 2: Isolating valves.

BS EN 1074-6, Valves for water supply Fitness for purpose requirements and appropriate verificationtests Part 6: Hydrants.

BS EN 1092-2, Flanges and their joints Circular flanges for pipes, valves, fittings and accessories,PN designated Part 2: Cast iron flanges.

BS EN 1092-3, Flanges and their joints Circular flanges for pipes, valves, fittings and accessories,PN designated Part 3: Copper alloy flanges.

BS EN 1503-3, Valves Materials for bodies, bonnets and covers Part 3: Cast irons specified inEuropean Standards.

BS EN 1561, Founding Grey cast irons.

BS EN 1563, Founding Spheroidal graphite cast iron.

BS EN 1982, Copper and copper alloys Ingots and castings.

BS EN 10088-1, Stainless steels Part 1: List of stainless steels.

6) To be published in 2004.



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Documents

BS 750-1984 - Specification for Underground Fire Hydrants & Surface Box Frames & Covers.pdf