AS 1301.457:2020 pdf free download – Methods of test for pulp and paper Method 457: Determination of moisture content in paper, board and pulps

AS 1301.457:2020 pdf free download – Methods of test for pulp and paper Method 457: Determination of moisture content in paper, board and pulps.
5 Apparatus
5.1 Balance
A balance having an accuracy of 0.05% of the mass to be weighed, or better.
5.2 Containers
Containers for preventing changes in moisture content during the transporting and weighing of test pieces, having airtight lids or other equivalent means of sealing, and made from a lightweight material not subject to change under conditions of drying specified in this document. Where test pieces are taken according to AS/NZS 1301.417s, the containers need to be large enough to contain sheets without cutting or tearing them, Before using a container, determine Its tare weight.
5.3 Drying oven
A drying oven capable of being maintained at an air temperature of 105 ± 2°C in the usable volume and having forced ventilation.
5.4 Desiccator
A dessicator equipped with freshly dried desiccant.
6 Sampling
Take a sample which is representative of the paper, board or pulp the moisture content of which is to be determined
Two standard sampling procedures for determining the moisture content of a lot exist, although any alternative procedure may be followed
NOTE When the purpose Is to obtain test pieces from a lot of paper or hoard, AS/NZS 1301.417s may be followed. When the purpose is to obtain test pieces from a lot of pulp In bale or roll form, AS/NZS ISO 7213 may be followed.
Throughout the chosen sampling procedure, minimize the chance of the sampled material losing or gaining moisture in exchange with the ambient air by wrapping the sample. Avoid moisture gain of the sampled material from tontact with the skin by wearing gloves.
Take sufficient sample material to ensure that the mass of moisture in a test piece can be determined to within 0.05 % of the mass of the test piece and so that additional test pieces can be obtained to permit the performance of replicate measurements if required. Enclose each test piece in a tared dry container (see Clause 5.2).
7 Procedure
7.1 Weighing of test piece
lithe test piece is hot when taken, ailow w cooi and equalize the air pressures inside and outside the container by momentarily opening and reclosing the lid immediately before weighing. Weigh the test piece in its container.
Use a 10 ml. receiver unless small masses of paper are to be taken, or low moisture contents ar anticipated, in which case a 2 ml. receiver may be used.
Before use, calibrate the receiver by adding measured volumes of water from a micro-pipette ofknow accuracy. The receiver should contain a small quantity of the immiscible liquid (heptarie or toluene) be used for the test, since the surface tension of the particular liquid used will affect the shape of th meniscus formed at the glass-water interface.
Before testing any samples, prepare a graph showing the water recovery by adding known volumes c water to the immiscible liquid in the distillation vessel and distil, following normal laboratory practice for 2 h. Read nit the volume of water recovered and plot against the volume of water added.
A.2.3 Immiscible liquid
Use heptane or toluene as the immiscible liquid. Saturate the immiscible liquid by carrying out preliminary distillation with the addition of water only to the distillation vessel. All of the solveri introduced needs to be retained in the system and all operations need to be done in an efficient fum cupboard and in accordance with AS/NZS 2243.2. Any equipment needs to be spark-free.
WARNING — TOLUENE AND HEPTANE ARE HIGHLY FLAMMABLE IN LIQUID OR VAPOUR FOR
AND FORM EXPLOSIVE MIXTURES WITH AIR. PROLONGED EXPOSURE TO THE VAPOUR MA’ CAUSE DROWSINESS OR DIZZINESS. TOLUENE IS A CARCINOGEN WHEN ABSORBED THROUGI THE SKIN OR INHALED AS A VAPOUR. IT IS ALSO POISONOUS. FOR FURTHER DETAILS 0 HAZARDOUS MATERIALS REFER TO THE AS 2508 SERIES.