BS EN 14243-3 pdf free download

BS EN 14243-3-2019 pdf free download.Materials obtained from end of life tyres Part 3: Shreds, cuts and chips – Methods for determining their dimension(s) including protruding filaments dimensions.
5.2.2 Preparation of the sampling plan for determining dimensions
The first step is to identify the properties required in the testing programme and the lot in relation to which they are defined, for instance TMmaximum projected length on a shreds production of 300 t”.
The lot size is based on production quality management decisions or specific customer requirements. The lot size may he defined by the producer as a fixed quantity produced between machine settings or a fixed quantity in a production day/shift/week or a fixed quantity. With regards to certain pieces exhibiting large dimensions, the tools for taking an increment shall be sufficiently large in order that the large pieces are equally sampled. For shreds, this typically results in increments of more than 200 pieces (about 3 kg to 15 kg).
NOTE 1 Larger increments would slightly improve the sampling quality, while increasing the size of the field sample, therefore complicating the size reduction Into laboratory sample(s). It Is preferable to Increase the number of increments, thus increasing directly the representativeness.
For reference testing (contractual or pre-contractual) concerning shreds dimension(s) the field sample is a composite sample constituted of three increments taken at dates selected randomly along the period of time during which the lot is produced. When at one date there are no shreds at the sampling location, the increment is taken at another date preselected prior to sampling, unless this is caused by a major change in the production process (see below).
For routine testing concerning the dimension(s) of shreds the field sample consists of one increment taken at a date selected randomly along the period of time during which the lot is produced. When at this date there are no shreds at the sampling location, the increment is taken at another date preselected prior to sampling, unless this is caused by a major change in the production process (see below).
During a sampling step the production process may be interrupted by a major change. Such a major change would induce in the sample two different subpopulations, before and after the major change. Therefore, it is necessary to consider a lot before and a lot after the major change. Major changes may occur on the feed and on the production process.
NOTE 2 The random taking of three increments allows having a first approximation of the variability inside the considered lot. The random taking of one increment in routine testing allows also another evaluation of the variability when considering the lots obtained under comparable conditions.
5.3 Procedure for taking the field sample and producing the laboratory sample(s)
Taking increment(s) at the output of the conveyer in the falling zone. The used tool is typically a rectangular open scoop. i.e. without an edge on one of the long side capable of cutting” the entire flow. Such a scoop (see Annex.B) shall have:
a) a width L at least 1.5 times the width of the falling flow;
b) a depth Pat least 2/3 of the width Land at least 2,5 times the higher dimension HDF;
c) an edge height H equal at least to 1/3 of the width Land at least two times the higher dimension HDF. This scoop is moved for instance with a loader according to a detailed procedure adapted to the site condition. This scoop can be the bucket of a loader, provided that its cleanliness is compatible with the requirement of the dimension measurement, i.e. the absence of deposit. The taken increment is
considered as valid if both criteria are fulfilled:
— the increment consists of at least 200 pieces for shreds (after sieving of fines);
— the mass of the increment does not exceed 15 kg for shreds.
NOTE The minimum size of the increment is specified as a minimum number of pieces in view of the statistical evaluation of the measurements of the maximum projected length of each piece. A specification in mass would result in significant differences depending on the size of the pieces.
For the determination of dimension(s), each increment constitutes a laboratory sample for such determination. If there are several increments, the dimension of each increment is determined and the average is calculated. This is easier than reducing the size of the field sample prior to measurement of the dimension.
5.4 PrincIple of determining the dimension(s)
A laboratory sample of at least TNP> 200 that do not pass through the LDF mm sieve is taken for the test. The MS mass (in grams) of this laboratory sample is weighed to within ± 0,01 kg. Any elements consisting solely of metal wires released from the pieces of end-of-life tyre are not counted in the TNP pieces. They are collected and weighed together (MLM g).
After passing through a LDF mm sieve, the mass (in grams) of the fine pieces (MF) is weighed to within ± 0,01 kg. The pieces that do not pass through the sieve (without loose metal wires) are used to determine the maximum lengths and constitute the test portion for determination purposes.
Each piece of this test portion is treated individually. As these pieces are not usually flat, the largest length is defined as the largest length projected onto a plane on which the piece in question lies. This length is measured to within ± 5 mm, without deforming the piece and excluding filaments.
The measurements of the different maximum projected lengths L are used to build a histogram (see Figure 2) that is characteristic of the distribution of the pieces of the test portion, i.e. the laboratory sample without the fine pieces and without the loose metal wires. This histogram consists of the large pieces class (larger than the HDF threshold dimension of the large pieces) and NCR = 7 classes of the same width between the LDF and HDF dimensions.
Three characteristics of the histogram are extracted from these measurements:
a) the number percentage of large pieces (NPL) (%) (and optionally, the mass percentage of large pieces (MPL) (%)) corresponding to the pieces larger than the higher dimension of the HDF format (I-IDF is one of the characteristics of the format of the product under consideration, for example 350 mm);
b) the mass percentage of the fine pieces (MPF) (%) = 100 x MF/MS (mass percentage of the pieces passing through the sieve with a mesh of LDF mm) (LDF is one of the characteristics of the product format under consideration, for example 25 mm);
c) the number percentage (N PC) (%) (and optionally the mass percentage (MPC) (%)) of the pieces in the number of NCC central classes (2-3-4-5-6) amongst the NCR = 7 classes between the lower and higher dimensions of the format (LDF and HDF).BS EN 14243-3 pdf download.