{"id":315795,"date":"2024-10-19T21:46:22","date_gmt":"2024-10-19T21:46:22","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/bs-en-iso-6145-72018\/"},"modified":"2024-10-25T19:55:08","modified_gmt":"2024-10-25T19:55:08","slug":"bs-en-iso-6145-72018","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/bsi\/bs-en-iso-6145-72018\/","title":{"rendered":"BS EN ISO 6145-7:2018"},"content":{"rendered":"<p>ISO&nbsp;6145 is a series of documents dealing with various dynamic methods used for the preparation of calibration gas mixtures. This document specifies a method for continuous preparation of calibration gas mixtures, from nominally pure gases or gas mixtures by use of thermal mass-flow controllers. The method is applicable to preparation of mixtures of non-reacting species, i.e. those which do not react with any material of construction of the flow path in the thermal mass-flow controller or the ancillary equipment.<\/p>\n<p>If this method is employed for preparation of calibration gas mixtures the optimum performance is as follows: the relative expanded measurement uncertainty <i>U<\/i>, obtained by multiplying the standard uncertainty by a coverage factor <i>k<\/i>&nbsp;=&nbsp;2, is not greater than 2&nbsp;%.<\/p>\n<p>If pre-mixed gases are used instead of pure gases, mole fractions below 10<sup>\u22126<\/sup> can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration.<\/p>\n<p>The merits of the method are that a large quantity of the calibration gas mixture can be prepared on a continuous basis and that multi-component mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.<\/p>\n<blockquote>\n<p>NOTE Gas blending systems, based upon thermal mass-flow controllers, and some including the facility of computerization and automatic control, are commercially available.<\/p>\n<\/blockquote>\n<h4>PDF Catalog<\/h4>\n<table border=\"1px\" class=\"des-table\">\n<tr>\n<th>PDF Pages<\/th>\n<th>PDF Title<\/th>\n<\/tr>\n<tr>\n<td><b>2<b><\/td>\n<td>National foreword  <\/td>\n<\/tr>\n<tr>\n<td><b>4<b><\/td>\n<td>European foreword  <\/td>\n<\/tr>\n<tr>\n<td><b>6<b><\/td>\n<td>Foreword  <\/td>\n<\/tr>\n<tr>\n<td><b>7<b><\/td>\n<td>1 Scope <br \/> 2 Normative references <br \/> 3 Terms and definitions  <\/td>\n<\/tr>\n<tr>\n<td><b>8<b><\/td>\n<td>4 Symbols <br \/> 5 Principle <br \/> 6 Set-up <br \/> 6.1 General  <\/td>\n<\/tr>\n<tr>\n<td><b>9<b><\/td>\n<td>6.2 Thermal mass-flow controller using a constant current supply <br \/> 6.3 Thermal mass-flow controller under constant temperature control  <\/td>\n<\/tr>\n<tr>\n<td><b>10<b><\/td>\n<td>7 Preparation of gas mixtures <br \/> 7.1 Description of the experimental procedure  <\/td>\n<\/tr>\n<tr>\n<td><b>12<b><\/td>\n<td>7.2 Range of validity <br \/> 7.3 Operating conditions  <\/td>\n<\/tr>\n<tr>\n<td><b>13<b><\/td>\n<td>8 Calculations <br \/> 8.1 Volume fraction <br \/> 8.2 Sources of uncertainty  <\/td>\n<\/tr>\n<tr>\n<td><b>14<b><\/td>\n<td>8.3 Uncertainty of measurement  <\/td>\n<\/tr>\n<tr>\n<td><b>15<b><\/td>\n<td>Annex A (informative) Pre-mixed gases for the preparation of mixtures of high dilution  <\/td>\n<\/tr>\n<tr>\n<td><b>16<b><\/td>\n<td>Annex B (informative) Practical hints  <\/td>\n<\/tr>\n<tr>\n<td><b>18<b><\/td>\n<td>Annex C (informative) Calculation of uncertainties  <\/td>\n<\/tr>\n<tr>\n<td><b>21<b><\/td>\n<td>Bibliography  <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":"<p><b>Gas analysis. Preparation of calibration gas mixtures using dynamic methods &#8211; Thermal mass-flow controllers<\/b><\/p>\n<table class=\"shortdes-table\" style=\"width: 100%\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td>Published By<\/td>\n<td>Publication Date<\/td>\n<td>Number of Pages<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/pdfstandards.shop\/product-category\/publishers\/bsi\/\"><b>BSI<\/b><\/a><\/td>\n<td>2019<\/td>\n<td>22<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":315800,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[1000,2641],"product_tag":[],"class_list":{"0":"post-315795","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-71-040-40","7":"product_cat-bsi","9":"first","10":"instock","11":"sold-individually","12":"shipping-taxable","13":"purchasable","14":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/315795","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/315800"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=315795"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=315795"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=315795"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}