ISO 4324-1977 PDF

Full title and description

ISO 4324:1977 — Surface active agents — Powders and granules — Measurement of the angle of repose. This International Standard specifies a simple, reproducible procedure for determining the angle of repose (base/cone angle) of powders and granular forms of surface-active agents (surfactants) and similar materials by forming a cone from a fixed funnel and measuring the geometry of the cone produced.

Abstract

ISO 4324:1977 describes a funnel/cone method to assess flow and bulk behaviour of powders and granules used in surfactant products (for example detergents). A defined volume of product is passed through a standard funnel positioned at a fixed height above a flat plate; the resulting conical pile is measured and the base angle (angle of repose) is calculated. The method is applicable to surfactant powders and other powders/granules with comparable flow characteristics.

General information

• Status: Published (International Standard) — reviewed and confirmed in 2024, remains current.
• Publication date: 1 September 1977 (Edition 1).
• Publisher: ISO — International Organization for Standardization.
• ICS / categories: 71.100.40 (Surface-active agents).
• Edition / version: Edition 1 (1977).
• Number of pages: 3.

Scope

This standard gives a laboratory procedure to determine the angle of repose of surfactant powders and granules and other materials with similar flow properties. It covers the equipment geometry (funnel, base plate), sample volume, funnel height, precautions to ensure repeatability and the calculation of the angle from measured cone dimensions. It is intended for quality control, formulation development and inter‑laboratory comparison where a simple comparative flow-test is required.

Key topics and requirements

• Defined apparatus: standardized funnel outlet, support with a fixed opening mechanism, level flat base plate or disc to form the cone.
• Specified test specimen volume and funnel height above the base to ensure comparable cone formation.
• Procedure steps: fill funnel with a representative test portion, allow material to flow without vibration until the cone forms, stop flow and measure cone geometry.
• Measurements required: cone height and base diameter (or base radius). Angle of repose α calculated from geometry (commonly α = arctan(h/r), where h = cone height and r = base radius).
• Repeatability considerations: prescribed number of repeats, handling instructions, and notes on moisture, segregation and particle size effects that influence results.
• Applicability statement: intended primarily for surfactant powders and washing powders but applicable to other powders/granules with comparable behaviour; not suitable for very cohesive or highly fluidized materials.

Typical use and users

Used by quality control and R&D laboratories in chemical and detergent manufacturing, formulation scientists, raw material suppliers, test laboratories and equipment manufacturers. Typical uses include raw-material acceptance testing, formulation screening, comparative flowability checks, and basic process-design input for storage/handling equipment (hoppers, feeders).

Related standards

Standards commonly related to ISO 4324:1977 include other ISO methods for surface-active agents published in the same series (for example ISO methods addressing non‑ionic/aspect determinations) and national/adopted versions (e.g., DIN ISO 4324). General standards on powder flow and bulk properties (test methods for pourability, bulk density, tapped density) and standards for measuring equipment (for example standards for measuring cylinders) are frequently used alongside ISO 4324 in laboratory test programs.

Keywords

angle of repose; repose angle; powder flow; granular materials; surfactants; surface-active agents; cone method; funnel test; flowability; detergents; quality control.

FAQ

Q: What is this standard?

A: ISO 4324:1977 is an ISO International Standard that specifies a funnel/cone method for measuring the angle of repose of powders and granules, with primary application to surface-active agents (surfactants) and similar materials.

Q: What does it cover?

A: It covers the apparatus and a step-by-step procedure for forming a cone by pouring a defined volume through a funnel at a fixed height, how to measure cone dimensions and how to calculate the angle of repose; it also notes applicability limits and repeatability considerations.

Q: Who typically uses it?

A: Quality-control and research laboratories in chemical and detergent industries, material suppliers, test houses and equipment vendors who need a simple comparative measure of powder/granule flow properties.

Q: Is it current or superseded?

A: ISO 4324:1977 remains the published edition (Edition 1, 1977). The standard was reviewed and confirmed in 2024 and is listed as current (published). Users should check national adoption or amendments for local designations (for example DIN adoptions).

Q: Is it part of a series?

A: Yes — it forms part of a group of ISO methods addressing physical and analytical tests for surface-active agents (other ISO documents from the same technical area were published around the same period). It is often used together with related powder and surfactant test methods.

Q: What are the key keywords?

A: Angle of repose, powder flow, cone method, surfactants, powders, granules, funnel test, flowability, detergents.