Ministry of Defence. Defence Standard /Issue 2 28 February 1997 CALCIUM HYPOCHLORITE

Transcription

1 Ministry of Defence Defence Standard /Issue 2 28 February 1997 CALCIUM HYPOCHLORITE This Defence Standard supersedes INTERIM Def Stan /Issue 1 dated 1 December 1989

2 AMENDMENTS ISSUED SINCE PUBLICATION AMD NO DATE OF TEXT AFFECTED SIGNATURE & ISSUE DATE Revision Note This Defence Standard has been updated from an INTERIM Defence Standard, and incorporates Laboratory Method M925. Historical Record TS 10202A dated 14 July 1982 Laboratory Method M925/88 dated 19 May 1988 INTERIM Def Stan /1 dated 1 December 1989

3 CALCIUM HYPOCHLORITE PREFACE This Defence Standard supersedes INTERIM Def Stan /Issue 1 dated 1 December 1989 i This Defence Standard specifies requirements for calcium hypochlorite. ii This Standard has been produced on behalf of the Defence Engineering and Equipment Standardization Committee (DEESC) by the Explosives Subcommittee (E15). iii This Standard has been agreed by the authorities concerned with its use and is intended to be used whenever relevant in all future designs, contracts, orders etc and whenever practicable by amendment to those already in existence. If any difficulty arises which prevents application of the Defence Standard, the Directorate of Standardization shall be informed so that a remedy may be sought. iv Any enquiries regarding this Standard in relation to an invitation to tender or a contract in which it is incorporated are to be addressed to the responsible technical or supervising authority named in the invitation to tender or contract. v This Standard has been devised for the use of the Crown and its contractors in the execution of contracts for the Crown. The Crown hereby excludes all liability (other than liability for death or personal injury) whatsoever and howsoever arising {including, but without limitation, negligence on the part of the Crown its servants or agents) for any loss or damage however caused where the Standard is used for any other purpose. 1

4 CONTENTS Preface 1 Scope 2 WARNING 3 Related Documents 4 Description 5 Test Requirements 6 Containers and Marking of Containers PAGE Table A Annex A Test Requirements Examination of Calcium Hypochlorite 4 A-1 2

5 CALCIUM HYPOCHLORITE 1 Scope This Defence Standard hypochlorite used for 2 WARNING specifies requirements for a grade of calcium water purification and for sanitary uses. This Standard calls for the use of substances and/or procedures that may be injurious to health if adequate precautions are not taken. It refers only to technical suitability and in no way absolves either the designer, the producer, the supplier or the user from statutory and all other legal obligations relating to health and safety at any stage of manufacture or use. 3 Related Documents 3.1 The following publications are referred to in the text of this Standard: BS 410 BS 846 BS 1583 BS 1752 BS 1792 BS 3978 BS 4385: Part 1 Specification Specification Specification Specification for for for for Test Sieves Burettes One-mark Pipettes Laboratory Sintered or Fritted Filters Including Porosity Grading Specification for One-mark Volumetric Flasks Specification for Water for Laboratory Use Methods for Determination of Water in Crude Petroleum, Petroleum Products and Bituminous Materials by Distillation: Method for Crude Petroleum 3.2 Reference in this Standard to any related document, means in any invitation to tender or contract the edition and all amendments current at the date of such tender or contract unless a specific edition is indicated. 3.3 Related documents can be obtained from: DOCUMENT SOURCE British Standard (BS) BSI Customer Services 389 Chiswick High Road LONDON W4 4AL 3

6 4 Description The material shall consist essentially of calcium hypochlorite as a white free-flowing granular powder free from visible impurities and foreign matter. A proportion of inorganic salt impurities may be present. 5 Test Requirements Samples taken from any portion of the supply shall be in accordance with clause 4 and, when tested by the method specified, shall comply with the requirements of table A. Table A - Test Requirements ITEM PROPERTY REQUIREMENT METHOD OF NO TEST (Clause No) 1 Available chlorine, % 65 min A.2 2 Stability - available chlorine after 2 hours at 100 C, % 35 min A.3 3 ph of a 5% solution 10.5 min A.4 4 Matter insoluble in water, % 5.0 max A.5 5 Water content, % 11.0 max A.6 6 Sievinq: Retained on a 2.8 mm sieve Nil A.7 Retained on a 2.0 mm sieve, % 1.0 max A.7 Retained on a 1.4 mm sieve, % 5.0 max A.7 Retained on a 150 µm sieve, % 85 min A.7 Particulars of the sieves may be found in BS 410 NOTE: If any sample taken from the consignment be found not to comply with the requirements of this Standard, the whole consignment may be rejected. 6 Containers and Marking of Containers 6.1 The material shall be supplied in sound, clean and dry containers suitable for the product and in accordance with the requirement of the contract or order. The use of contaminated containers may render the whole consignment liable for rejection. After filling, each container shall be securely closed. 4

7 6.2 It is the manufacturer s responsibility to mark containers in accordance with any legal requirements. In addition, the containers shall be both legibly and durably marked with the following details: Designation viz: CALCIUM HYPOCHLORITE Defence Standard number viz: DEF STAN /2 Contractor or order number: Distinctive lot and/or batch number: Quantity of contents: Date of manufacture: Manufacturer s name, initials or recognized trade mark: and any other markings called for in the contract or order. 5

8 ANNEX A Examination of Calcium Hypochlorite A.1 General Requirements Unless otherwise instructed, following shall be used: weighings (W) shall be to ± g and the A.1.1 Apparatus: Sieves complying with BS 410. Burettes complying with BS 846 (class A). One-mark pipettes complying with BS 1583 (class A). Sintered or fritted filters complying with BS One-mark volumetric flasks complying with BS 1792 (class A). A.1.2 Reagents: Chemicals of analytical reagent quality. Water complying with BS 3978, grade 3. A.2 Determination of Available Chlorine A.2.1 Reaqents: Sodium thiosulfate 0.1M accurately standardized. Acetic acid (d = 1.05 g/cm 3 ). Potassium iodide (iodate free). Starch solution 1% m/v freshly prepared, or suitable proprietary iodine indicator. A.2.2 Procedure. Weigh accurately (2.5 ± 0.1)g (W l ) of the sample into a small, glass mortar and, using a glass pestle, rub into a cream with 15 to 20 cm 3 of water. When the material is thoroughly dispersed, add cold water to a total volume of about 100 cm 3. Allow any coarse particles to settle and decant the turbid liquor into a 500 cm 3 one-mark volumetric flask. Continue grinding the residue with further quantities of water, decanting the supernatant liquor into the flask, until only insoluble gritty matter remains. Make up to the mark with water and mix the solution well. Pipette 50 cm 3 of the well-mixed suspension into a 400 cm 3 conical flask. Add 25 cm 3 of water, (2.0 ± 0.1)g of the potassium iodide and 10 cm 3 of the acetic acid. Titrate with the sodium thiosulfate until the solution is pale yellow in colour. Add approximately 2 to 3 cm 3 of the starch solution and continue the titration to a colourless end-point (V l ). Add the sodium thiosulfate dropwise near to the end-point with vigorous swirling of the reaction mixture between each addition. A-1

9 ANNEX A (Continued). A.2.3 Calculation. Available chlorine, per cent = x V 1 W 1 A.3 Determination of Stability at 100 C A.3.1 Apparatus: Test-tube 150 x 25 mm. A.3.2 Procedure. Fill the test-tube to a depth of about 120 mm with the sample and tap the tube lightly on the bench at least three times to consolidate the powder. Into the mouth of the test-tube, fit a rubber stopper carrying a piece of glass tubing 370 mm long by 5 mm internal diameter, leaving 10 mm of the tubing projecting below the base of the stopper. Place the test-tube in a water-bath maintained at (100 ± 2) C. After 2 hours remove the test-tube from the bath and replace the stopper carrying the glass tubing with a solid stopper. Allow to cool for 10 minutes, then transfer the sample to a bottle. Shake the bottle well and determine the available chlorine content as described in A.2. A.4 Determination of ph of a 5% Aqueous Solution A.4.1 Apparatus: ph meter fitted with suitable electrodes. A.4.2 Procedure. Dissolve (5.0 ± 0.1)g of the sample in 100 cm 3 of water and determine the ph value of the solution using the ph meter. The electrodes must be thoroughly washed with water and the instrument must be calibrated, using buffer solutions, before each series of determinations. A.4.3 Reportinq. Report the result to the nearest 0.1 ph unit. A.5 Determination of Matter Insoluble in Water A.5.1 Procedure. Transfer (1.0 ± 0.01)g of the sample to a 600 cm 3 beaker and add 400 cm 3 of water at 70 C. With the mixture maintained at 70 C stir gently for 30 minutes and filter the solution through a tared (W 2 ) P16 sintered-glass crucible. Wash the residue with a further 400 cm 3 of water at 70 C. Finally wash any residue remaining in the beaker into the crucible with 200 cm 3 of water at 70 C. Dry the crucible in an oven maintained at (103 ± 2) C. After 1 hour, cool the crucible for 30 minutes in a desiccator containing freshly activated silica gel and reweigh (W 3 ). A.5.2 Calculation Matter insoluble in water, per cent = (W 3 - W 2 ) x 100. A-2

10 ANNEX A (Concluded) A.6 Determination of Water Content A.6.1 Procedure. Determine the water content by the procedure described in BS 4385: Part 1, using a 15 g portion (W 4 ) of the sample and a solvent mixture containing one part by volume of toluene and four parts by volume of xylene. Note the volume (V 2 ) of water in cm 3 collected in the receiver. NOTE: A.6.2 The determination shall be carried out in a fume cupboard. Calculation Water content, per cent = V 2 x 100 W 4 Sievinq A.7.1 Apparatus: Sieves 200 mm in diameter, sizes. 2.8 mm, 2.0 mm, 1.4 mm and 150 µm aperture Receiver. Soft-hair brush 25 mm wide. A.7.2 Procedure. Assemble a nest of the sieves with the receiver. Transfer (20.0 ± 0.1)g of the sample to the top sieve. Brush gently until no more material appears to pass the sieve. Remove the top sieve and continue brushing the material on the next sieve. Repeat the process on each sieve in turn. Weigh the material retained on each sieve. A.7.3 Reportinq. Report the amount of material retained on each sieve as percentage by mass of the original sample. A-3

11 Collation Page

12 Crown Copyright 1997 This Standard may be fully reproduced Published by and obtainable from: except for sale purposes. The following conditions must be observed: Ministry of Defence 1 The Royal Coat of Arms and the Directorate of Standardization publishing imprint are to be Kentigern House omitted. 65 Brown Street 2 The following statement is to be GLASGOW G2 8EX inserted on the cover: Crown Copyright. Reprinted by Tel: (name of organization) with the Fax: permission of Her Majesty s Stationery Office. Requests for commercial reproduction should be addressed to MOD Stan 1, Kentigern House, 65 Brown Street, Glasgow G2 8EX The following Defence Standard file reference relates to work on this Standard - D/D Stan/310/7/00. Contract Requirements When Defence Standards are incorporated into contracts users are responsible for their correct application and for complying with contract requirements. Revision of Defence Standards Defence Standards are revised when necessary by the issue either of amendments or of revised editions. It is important that users of Defence Standards should ascertain that they are in possession of the latest amendments or editions. Information on all Defence Standards is contained in Def Stan (Part 3) Section 4, Index of Standards for Defence Procurement - Index of Defence Standards and Specifications published annually and supplemented periodically by Standards in Defence News. Any person who, when making use of a Defence Standard encounters an inaccuracy or ambiguity is requested to notify the Directorate of Standardization without delay in order that the matter may be investigated and appropriate action taken. 92/50041