1、BSI Standards PublicationBS 8618:2015Granular carbon dioxide(CO2) absorbent material forlife support, diving,hyper- and hypobaricapplications SpecificationPublishing and copyright informationThe BSI copyright notice displayed in this document indicates when the documentwas last issued. The British S
2、tandards Institution 2015Published by BSI Standards Limited 2015ISBN 978 0 580 88169 5ICS 71.060.20; 71.100.20The following BSI references relate to the work on this document:Committee reference PH/4/7Draft for comment 15/30313784 DCPublication historyFirst published July 2015Amendments issued since
3、 publicationDate Text affectedBS 8618:2015 BRITISH STANDARDContentsForeword iiIntroduction 11 Scope 12 Normative references 13 Terms, definitions and abbreviations 14 Requirements 25 Testing 36 Marking 137 Information supplied by the manufacturer 13List of figuresFigure 1 Schematic carbon dioxide ab
4、sorbent test rig 5Figure 2 Absorbent activity tube 7Figure 3 Snow storm filler for activity tube 8Figure 4 Snow storm filler (throat detail) 9List of tablesTable 1 Carbon dioxide absorbent activity 2Table 2 Carbon dioxide absorbent granule size 2Table 3 Friability for carbon dioxide absorbent materi
5、als 3Table 4 Nest of 250 mm diameter sieves 11Summary of pagesThis document comprises a front cover, an inside front cover, pages i to ii,pages 1 to 14, an inside back cover and a back cover.BRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 iForewordPublishing informationThis Brit
6、ish Standard is published by BSI Standards Limited, under licence fromThe British Standards Institution, and came into effect on 31 July 2015. It wasprepared by Subcommittee PH/4/7, Underwater breathing apparatus, under theauthority of Technical Committee PH/4, Respiratory protection. A list oforgan
7、izations represented on this committee can be obtained on request to itssecretary.Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Itsrequirements are expressed in sentences in which the principal auxiliary verb is“shall”.Commentary, explanation a
8、nd general informative material is presented insmaller italic type, and does not constitute a normative element.Requirements in this standard are drafted in accordance with Rules for thestructure and drafting of UK standards, subclause J.1.1, which states,“Requirements should be expressed using word
9、ing such as: When tested asdescribed in Annex A, the product shall .”. This means that only those productsthat are capable of passing the specified test will be deemed to conform to thisstandard.Contractual and legal considerationsThis publication does not purport to include all the necessary provis
10、ions of acontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legalobligations.BRITISH STANDARDBS 8618:2015ii The British Standards Institution 2015IntroductionGranular and pelleted carbon dioxide (CO2) absorbents are used in a va
11、riety oflife-support, diving, hyper- and hypobaric applications. The type andcharacteristics of absorbents vary dependent upon the intended use, differencesin manufacturing techniques and chemical composition.This standard provides requirements and test methods for carbon dioxideabsorbents, and desi
12、gnations for such absorbents. This allows users to selectappropriate materials for their intended application.1 ScopeThis British Standard gives requirements and test methods for granular andpelleted carbon dioxide absorbent materials.NOTE For the purposes of this standard, the term “granular” inclu
13、des bothgranular and pelleted material.It is applicable to granular carbon dioxide absorbents intended for use inlife-support applications including re-breathing apparatus on the surface andunderwater, hyperbaric, and hypobaric applications.It excludes granular and pelleted carbon dioxide absorbents
14、 intended for use inapplications in medical anaesthesiology, materials that also generate oxygen,and monolithic pre-formed materials or those embedded within a polymermatrix.2 Normative referencesBS ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sievesof metal wire cloth3 Te
15、rms, definitions and abbreviations3.1 Terms and definitionsFor the purposes of this British Standard, the following terms and definitionsapply.3.1.1 activity timetime (in minutes) that a carbon dioxide absorbent material can maintain aneffluent carbon dioxide level less than a given value3.1.2 granu
16、le/granular materialgranular or pelleted material3.1.3 friabilitypropensity to form dust3.1.4 indicatormaterial that changes colour as an absorbent is used3.2 AbbreviationsS-H Small soda lime, high-activityS-L Small soda lime, low-activityL-H Large soda lime, high-activityL-L Large soda lime, low-ac
17、tivityBRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 1Li-S Lithium hydroxide, smallLi-L Lithium hydroxide, large4 Requirements4.1 Absorbent designationsThe absorbent shall be a granular material of one of the following designations:a) For soda lime based materials:S-H, S-L, L-H
18、 or L-Lb) For lithium hydroxide based materials:Li-S or Li-LNOTE Requirements for associated granule sizes and dust-loads are given in 4.4,and requirements for friability are given in 4.5.4.2 Carbon dioxide absorbent activityThe carbon dioxide absorbent material shall have an absorbent activity inac
19、cordance with Table 1 when tested in accordance with 5.1.Table 1 Carbon dioxide absorbent activityCarbon dioxide absorbent material Absorbent activityS-H and L-H 90 minS-L and L-L 60 minLi-S and Li-L 125 min4.3 Volatile (water) contentThe absorbent material shall have the following volatile content,
20、 when tested inaccordance with 5.2:S-H, L-H, S-L and L-L, between 14% and 22%.Li-S and Li-L, 1.0%.4.4 Carbon dioxide absorbent granule size and dust loadThe granule sizes and dust loads of the absorbent material shall be inaccordance with Table 2, when tested in accordance with 5.3.Table 2 Carbon di
21、oxide absorbent granule sizeGranule size Limits (weight %)Small-granule Large-granuleRetained on 5.60 mmsieve 1.0 maxRetained on 4.75 mmsieve 7.0 maxRetained on 2.80 mmsieve1.0 max Retained on 2.00 mmsieve30.0 max 76.0 minBRITISH STANDARDBS 8618:20152 The British Standards Institution 2015Table 2 Ca
22、rbon dioxide absorbent granule sizeGranule size Limits (weight %)Small-granule Large-granuleRetained on 1.40 mmsieve48.0 min Retained on 0.60 mmsieve20.0 max 15.0 maxPassing 0.60 mm sieve(dust)0.50 max 0.50 max4.5 FriabilityThe absorbent material friability shall be in accordance with Table 3, whent
23、ested in accordance with 5.4.NOTE Table 3 allows for higher dust level as this is created during the friabilitytest.Table 3 Friability for carbon dioxide absorbent materialsGranule size Limits (weight %)Small-granule Large-granuleRetained on 5.60 mm sieve 1.0 maxRetained on 4.75 mm sieve 7.0 maxReta
24、ined on 2.80 mm sieve 1.0 max Retained on 2.00 mm sieve 30.0 max 76.0 minRetained on 1.40 mm sieve 48.0 min Retained on 0.60 mm sieve 20.0 max 15.0 maxPassing 0.60 mm (dust) 1.0 max 1.0 max4.6 Flow resistanceThe absorbent material shall have the following flow resistance when tested inaccordance wit
25、h 5.5:S-H, S-L and Li-S: 1.4 mbar.L-H, L-L and Li-L, 1.2 mbar.4.7 IndicatorsThe absorbent material shall contain no indicators, when tested in accordancewith 5.6.5 TestingWARNING.Carbon dioxide absorbents consisting of (or containing) lithium hydroxide areharmful by inhalation and corrosive to skin
26、and eyes.BRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 35.1 Carbon dioxide absorbent activity5.1.1 PrincipleTo pass a known concentration of carbon dioxide through a predeterminedsample size to determine the time to achieve 0.50% v/v carbon dioxide at theoutlet.5.1.2 Apparatus
27、5.1.2.1 absorbent test rig, in accordance with Figure 1.5.1.2.2 activity tube, in accordance with Figure 2.5.1.2.3 snow storm filler, in accordance with Figure 3 and Figure 4.5.1.2.4 carbon dioxide analysers, capable of measuring an inlet carbon dioxideconcentration of 5% v/v 0.05% and an effluent c
28、oncentration of 0.5% v/v0.01%.5.1.3 Preparation and preservation of test samples and test piecesAssemble a test rig as shown in Figure 1.Locate the activity tube, as shown in Figure 2, into the base of a snow stormfiller as detailed in Figure 3 and Figure 4.Pour the absorbent at an even rate into th
29、e snow storm filler till the activitytube is filled to the 105 ml calibration mark. The mass (g) of absorbent added tothe tube shall be recorded.5.1.4 ProcedureThe test shall be repeated a minimum of three times, with the activity being theshortest recorded time. The tests to determine the activity
30、at atmosphericpressure shall be conducted at (20 1) C and in accordance with the followingprocedure:Insert the activity tube into the test rig; the tube shall be vertical, with the testgas flowing top to bottom. Pass a flow of (3.0 0.1) l/min of homogenous(5.0 0.05%) v/v carbon dioxide in nitrogen (
31、or air) test gas mixture, maintainedat (20 1) C, through the humidifiers and activity tube.A sample of both inlet and effluent gas exiting the activity tube shall be drawnoff and passed into a suitably ranged closed-loop carbon dioxide analysers, at asufficient rate to provide accurate analysis.The
32、sample gas shall pass through a drying agent that will not absorb carbondioxide (e.g. MgClO4) before passing into the gas analyser.The output signal from the inlet sample analyser and effluent sample analysershall be recorded.5.1.5 Expression of resultsRecord the time taken for the effluent gas to r
33、each a level of 0.50% v/v carbondioxide.BRITISH STANDARDBS 8618:20154 The British Standards Institution 2015Figure1SchematiccarbondioxideabsorbenttestrigDimensionsinmmKey (overleaf)BRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 5Figure1Schematiccarbondioxideabsorbenttestrig1 2
34、3 4 5 65.0%CO2inN23.0lmin-1Temperature20C1MixingboxHumidifier Dryer Activitytube7 8 9 10 11-Absorbent CO2analyserManometer/differentialpressuregaugeChartrecorder/dataacquisitionsystemWatertrap/ventGasflowElectricalsignalcableBRITISH STANDARDBS 8618:20156 The British Standards Institution 2015Figure
35、2 Absorbent activity tubeDimensions in mmKey 1 1.5 MESHBRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 7Figure 3 Snow storm filler for activity tubeDimensions in mmBRITISH STANDARDBS 8618:20158 The British Standards Institution 2015Figure 3Key123456View on top endTypical section
36、 of tubeMESH (5/8) Pitch Wire 32 swg. Typical in 3 positionsDimension from bottom to the fill line on the sample tube shouldbe 148.5 mmDimensions of collarActivity tubeFigure 4 Snow storm filler (throat detail)Dimensions in mmBRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 9Figu
37、re 4Key1 Three support arms equi-spaced5.2 Volatile (water) content5.2.1 Volatile content method (a)5.2.1.1 PrincipleTo drive off the volatile component by heating to a predetermined temperatureuntil a constant weight is achieved.5.2.1.2 Apparatus5.2.1.2.1 automatic volatile content infrared balance
38、5.2.1.3 Preparation and preservation of test samples and test pieces5.2.1.4 ProcedureTransfer approximately 10 g of absorbent onto an automatic volatile contentinfrared balance and record (if required) the mass (MA1). Start the automaticdrying cycle at a nominal temperature of 150 C and record (if a
39、vailable) thepercentage volatile reading when the absorbent is dry and/or the mass of thedried absorbent (MA2).5.2.1.5 Expression of resultsIf required, the percentage volatile content (volatile matter, %) can becalculated using Formula (1):H20849MA1 MA2)MA1100(1)5.2.2 Volatile content method (b)5.2
40、.2.1 Apparatus5.2.2.1.1 dish, squat form min. 100 mm diameter and 20 mm depth, able towithstand temperatures in excess of 150 C5.2.2.2 fan stirred oven, capable of maintaining a temperature of (150 10) C5.2.2.3 ProcedureTransfer approximately 100 g of absorbent to a previously weighed (MM1) clean,dr
41、y dish and accurately weigh (MM2).Remove the lid and place the dish, with the lid alongside, in the fan stirred ovenmaintained at (150 10) C.After 120 min. replace the lid and transfer the dish to a desiccator, containingfresh active desiccant. Allow to cool for 30 min.Release the lid on the dish mo
42、mentarily and re-weigh (MM3).5.2.2.4 Expression of resultsThe percentage volatile content (volatile matter, %) shall be calculated usingFormula (2):H20849MM2 MM3)(MM2 MM1)100(2)BRITISH STANDARDBS 8618:201510 The British Standards Institution 20155.3 Carbon dioxide absorbent granule size and dust loa
43、d5.3.1 PrincipleTo determine the size distribution of the granular material using a nest ofstandard sieves.5.3.2 Apparatus5.3.2.1 sieves, clean, dry (see Table 4)5.3.2.2 mechanical sieve shaker, of known frequency and amplitude5.3.3 Preparation and preservation of test samples and test piecesPerform
44、 a visual inspection of the sieves shown in Table 4, in accordance withBS ISO 3310-1, 5.2, Test 1.Table 4 Nest of 250 mm diameter sievesSieve aperture size (mm) Small-granuleLarge-granule5.60 4.75 2.80 2.00 1.40 0.60 Receiver panWeigh and record each of the sieves and the receiving pan indicated in
45、Table 4.Assemble the nest of clean dry sieves indicated in Table 4 in order of aperturesize with the receiver pan at the base.5.3.4 ProcedureDistribute (100 0.1) g of absorbent onto the top sieve. Record the amount ofabsorbent used. Attach the lid and shake the assembled sieves for 5 min. on amechan
46、ical shaker.Remove the nest of sieves from the shaker and weigh the amount of materialretained on each sieve, and the dust passing into the receiver at the base of thenest. Any granules lodged in the meshes of a sieve shall be included as thematerial retained on the sieve.5.3.5 Expression of results
47、Report the mass of material on each sieve, and the dust in the receiver, as apercentage of the total mass of absorbent retained in the nest of sieves.5.4 Friability5.4.1 PrincipleTo determine the change in size distribution of the granular material followingan extended period of vibration on a nest
48、of standard sieves.BRITISH STANDARD BS 8618:2015 The British Standards Institution 2015 115.4.2 Apparatus5.4.2.1 sieves, clean, dry (see Table 4)5.4.2.2 mechanical sieve shaker, of known frequency and amplitude5.4.3 Preparation and preservation of test samples and test piecesPerform a visual inspect
49、ion of the sieves shown in Table 4, in accordance withBS ISO 3310-1, 5.2, Test 1.Weigh and record each of the sieves and the receiving pan indicated in Table 4.Assemble the nest of clean dry sieves indicated in Table 4 in order of aperturesize with the receiver pan at the base.5.4.4 ProcedureDistribute (100 0.1) g of absorbent on the top sieve. Record the amount ofabsorbent used. Attach the lid and shake the assembled sieves for 60 min. on amechanical shaker.Rem
