ISO 3688-2022 PDF

Full title and description

Pulps — Preparation of laboratory sheets for the measurement of optical properties. This International Standard specifies two procedures for preparing laboratory sheets prior to measuring optical properties: preparation of pads in a Büchner funnel (using filter paper or a wire screen) and preparation of laboratory sheets in a standard sheet former (conventional or Rapid Köthen).

Abstract

This document describes two laboratory procedures to produce test sheets from pulp for optical-property measurement. It is applicable to all wood pulps and most other pulps, but excludes pulps with very long fibres (unless fibres are reduced to about 2 mm), recycled pulps (see ISO 21993), and it is not intended for opacity measurements or for determining light scattering and absorption coefficients.

General information

• Status: Published.
• Publication date: 6 December 2022 (ISO publication stage: International Standard published 2022-12-06).
• Publisher: ISO — International Organization for Standardization.
• ICS / categories: 85.040 (Pulps).
• Edition / version: Edition 3 (2022).
• Number of pages: 8.

Scope

Specifies two procedures for the preparation of laboratory sheets for subsequent measurement of optical properties: (1) preparation of pads using a Büchner funnel with filter paper or wire screen, and (2) preparation of sheets in a standard sheet former (conventional or Rapid Köthen). The standard applies to wood pulps and most other pulps; it excludes pulps with very long fibres unless shortened to about 2 mm, excludes recycled pulps (reference ISO 21993), and does not cover opacity or the determination of light scattering and absorption coefficients.

Key topics and requirements

• Two accepted sheet-preparation methods: Büchner-funnel pads (with filter paper or wire screen) and standard sheet former methods (conventional or Rapid Köthen).
• Applicability to wood pulps and most other pulps; limitations for very long fibres and recycled pulps.
• Requirements for fibre length reduction where necessary (approx. 2 mm) before applying the methods.
• Instructions intended to ensure representative, reproducible laboratory sheets suitable for optical testing (conditioning, equipment configuration and handling practices are specified in the full text).
• Exclusions: not intended for opacity measurements or for determining light scattering and absorption coefficients.

Typical use and users

Used by pulp and paper laboratories, quality control and R&D teams in pulp mills, paper manufacturers, testing and certification labs, and research institutions that measure optical properties of pulp-derived sheets. Typical applications include comparative optical testing of pulps, evaluation of bleaching and chemical treatments, and support for product development where laboratory-prepared sheets are required for standardized optical measurements.

Related standards

Related documents include ISO 21993 (recycled pulps — referenced for exclusion) and other ISO/TC 6 standards covering pulp and paper test methods. Users typically consult companion ISO test methods for specific optical-property measurements and for conditioning and testing environment requirements.

Keywords

pulp, laboratory sheets, sheet former, Rapid Köthen, Büchner funnel, optical properties, pulp preparation, fibre length, test method, ISO 3688.

FAQ

Q: What is this standard?

A: ISO 3688:2022 is an International Standard that specifies two laboratory procedures for preparing pulp sheets used when measuring optical properties of pulps.

Q: What does it cover?

A: It covers preparation of laboratory sheets by (1) making pads in a Büchner funnel (using filter paper or a wire screen) and (2) producing sheets in a standard sheet former (conventional or Rapid Köthen). It sets out applicability, limitations (long fibres, recycled pulps), and procedural requirements needed to obtain reproducible test sheets.

Q: Who typically uses it?

A: Pulp and paper testing laboratories, mill and mill-laboratory personnel, R&D groups, and certification/testing bodies involved in measuring optical properties of pulp-derived sheets.

Q: Is it current or superseded?

A: Current — ISO 3688:2022 (Edition 3) was published on 6 December 2022. It supersedes the earlier ISO 3688:1999.

Q: Is it part of a series?

A: It is part of the body of ISO standards developed by ISO/TC 6 (pulps) and is related to other pulp and paper test standards; ISO 21993 is specifically referenced for recycled pulps.

Q: What are the key keywords?

A: pulp, laboratory sheet, sheet preparation, Büchner funnel, Rapid Köthen, optical properties, fibre length, ISO 3688.