ISO 5311:2026
(Main)Fertilizers — Determination of bulk density (tapped)
Fertilizers — Determination of bulk density (tapped)
This document specifies two methods for the determination of the bulk density (tapped) of solid fertilizers: the machine-tapping method (method 1); the hand-tapping method (method 2). These methods are applicable to dry fertilizers only. Neither method is suitable for materials which contain a large proportion of particles exceeding 5 mm in diameter. Method 2 is applicable only to spherical granules and to prills. It is not applicable to sharp-edged grains. NOTE Because of the differences in tapping technique, the two methods will not necessarily give the same value for the bulk density (tapped).
Engrais — Détermination de la masse volumique après tassement
General Information
- Status
- Published
- Publication Date
- 19-Feb-2026
- Technical Committee
- ISO/TC 134 - Fertilizers, soil conditioners and beneficial substances
- Drafting Committee
- ISO/TC 134/WG 1 - Fertilizers
- Current Stage
- 6060 - International Standard published
- Start Date
- 20-Feb-2026
- Due Date
- 12-Feb-2027
- Completion Date
- 20-Feb-2026
Relations
- Effective Date
- 16-Aug-2025
Overview
ISO/FDIS 5311 specifies standard procedures for determining the bulk density (tapped) of dry fertilizers. The document covers two complementary methods: the machine‑tapping method and the hand‑tapping method. Results provide essential information for packaging dimensioning, warehouse capacity planning and inventory management.
The standard applies to dry fertilizers only and is not suitable for materials containing a large proportion of particles exceeding 5 mm in diameter. Method 2 (hand‑tapping) is restricted to spherical granules and prills and is not appropriate for sharp‑edged grains.
Key Topics
- Scope and applicability: Two defined test methods for tapped bulk density of solid, dry fertilizers. Limitations for particle size and grain shape are specified.
- Sample preparation: Samples shall be reduced and prepared according to referenced sampling standards. If the fertilizer has absorbed moisture during transport or storage, drying in an environmental chamber with controlled low humidity is required before testing.
- Apparatus and accuracy: Typical equipment includes a balance accurate to 1 g, measuring cylinder and funnel assembly (as per ISO 3944), spatula (~120 × 20 mm) and, for hand tapping, a rod ~200 mm long and ~10 mm diameter. The tapping machine camshaft frequency is specified (250 min⁻¹ ± 15 min⁻¹) where machine tapping is used.
- Procedures:
- Machine‑tapping: Pour through a specified funnel (discharge 6–12 s), place cylinder in the tapping machine and apply 2 500 taps, remove collar, trim surplus and weigh.
- Hand‑tapping: Pour with slower discharge (20–25 s), tap the cylinder walls manually (2–3 taps/s), raise and drop the cylinder twice (2–3 mm) to complete compaction, then trim and weigh.
- Expression of results: Bulk density (tapped) is calculated as mass divided by the known cylinder volume (g/cm³). Two determinations on separate test portions are made and the arithmetic mean reported if repeatability criteria are met.
- Repeatability: The difference between two successive determinations by the same operator and apparatus shall not exceed 0.01 g/cm³.
Applications
- Packaging design: Accurate tapped bulk density helps calculate required package volumes and material selection.
- Storage and logistics: Improved planning of silos, warehouses and transport capacities by estimating compacted volumes.
- Quality control and specification: Routine laboratory testing to confirm product handling characteristics and ensure consistency across batches.
Related Standards
- ISO 3944 - Determination of bulk density (loose)
- ISO 7742 - Reduction of samples
- ISO 14820-2 - Sampling and sample preparation, Part 2: Sample preparation
For implementation, refer to the full ISO/FDIS 5311 text and the referenced ISO documents for sampling and loose bulk density procedures. The methods are practical, repeatable and deliver data that directly support packaging, storage and inventory decisions.
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Frequently Asked Questions
ISO 5311:2026 is a standard published by the International Organization for Standardization (ISO). Its full title is "Fertilizers — Determination of bulk density (tapped)". This standard covers: This document specifies two methods for the determination of the bulk density (tapped) of solid fertilizers: the machine-tapping method (method 1); the hand-tapping method (method 2). These methods are applicable to dry fertilizers only. Neither method is suitable for materials which contain a large proportion of particles exceeding 5 mm in diameter. Method 2 is applicable only to spherical granules and to prills. It is not applicable to sharp-edged grains. NOTE Because of the differences in tapping technique, the two methods will not necessarily give the same value for the bulk density (tapped).
This document specifies two methods for the determination of the bulk density (tapped) of solid fertilizers: the machine-tapping method (method 1); the hand-tapping method (method 2). These methods are applicable to dry fertilizers only. Neither method is suitable for materials which contain a large proportion of particles exceeding 5 mm in diameter. Method 2 is applicable only to spherical granules and to prills. It is not applicable to sharp-edged grains. NOTE Because of the differences in tapping technique, the two methods will not necessarily give the same value for the bulk density (tapped).
ISO 5311:2026 is classified under the following ICS (International Classification for Standards) categories: 65.080 - Fertilizers. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO 5311:2026 has the following relationships with other standards: It is inter standard links to ISO 5311:1992. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
ISO 5311:2026 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
International
Standard
ISO 5311
Fourth edition
Fertilizers — Determination of bulk
2026-02
density (tapped)
Engrais — Détermination de la masse volumique après tassement
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Preparation of test sample . 1
5 Method 1 — Machine-tapping method . 2
5.1 Principle .2
5.2 Apparatus .2
5.3 Procedure .2
6 Method 2 — Hand-tapping method . 2
6.1 Principle .2
6.2 Apparatus .2
6.3 Procedure .3
7 Expression of results . 3
7.1 Method of calculation and formula .3
7.2 Repeatability .3
8 Test report . 3
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 134, Fertilizers, soil conditioners and beneficial
substances.
This fourth edition cancels and replaces the third edition (ISO 5311:1992), of which it constitutes a minor
revision. The changes are as follows:
— the normative reference to ISO 8358 in Clause 4 was changed to ISO 14820-2.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
The bulk densities (loose and tapped) of a fertilizer provide information relative to the required size
of packaging materials, store-houses, stock-rooms, etc. Generally, the bulk density (tapped) is up t
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