SIST ISO 7850:1996 PDF

Name: SIST ISO 7850:1996 — Cellular plastics, rigid -- Determination of compressive creep
SKU: SIST ISO 7850:1996
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Cellular plastics, rigid -- Determination of compressive creep

Название (английский):

SIST ISO 7850:1996

Cellular plastics, rigid -- Determination of compressive creep

Статус документа:: Действующий
Формат:: Электронный (PDF)
Количество страниц:: 3
Дата публикации:: 1 января 1996 г.
ICS:: 83.100
Технический комитет:: IPMA - Polimer materials and products

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Описание (английский):

Specifies a method for the determination of compressive creep of rigid cellular plastics under specified conditions of load, temperature, relative humidity and time. Test specimes in form or rectangular parallelepipeds are placed between two flat plates and the specified load is applied as follows: procedure A) at standard conditions and procedure B) at agreed conditions of temperture and time. The difference in compressive deformation of the loaded specimen at standard atmospheric conditions and at elevated temperature after specified time shall be calculated.

Abstract

Похожие стандарты

Стандарты, упомянутые в описании

Overview

ISO 7850:1986 specifies a laboratory method for the determination of compressive creep of rigid cellular plastics (rigid foams). The standard defines how to apply a steady compressive load to rectangular or circular test specimens between two flat plates and measure deformation over time under controlled load, temperature, relative humidity and time. Test results quantify both the initial compressive deformation and the time-dependent creep for comparative evaluation and product qualification.

Key Topics and Requirements

Specimen geometry and preparation

Test specimens are rectangular parallelepipeds or circular sections; surfaces must be undamaged and, where integral skins are part of the product, retained.
Standardized specimen thickness is 50 ± 1 mm (minimum thickness 20 ± 1 mm). Minimum loaded surface area is specified (generally ≥ 25 cm²); for thicknesses > 50 mm the loaded area must be at least the square of the thickness.
Specimens must be cut without damage and conditioned per ISO 291 (normal atmosphere: 23 ± 2 °C, 50 ± 5 % RH) for at least 24 hours.

Apparatus

Dial micrometer (precision 0.1 mm) compliant with ISO 1923 or equivalent.
Temperature and humidity test chamber capable of ±2 °C and ±5 % RH control.
Compression machine with two flat plates (one mobile), plates guided to limit lateral movement and avoid bending; plate separation measured to 0.1 mm.

Test procedures

Procedure A: Load applied under standard conditions; initial thickness measured (H1), load applied and thickness measured at 60 ± 10 s (H2), then thickness measured at specified intervals.
Procedure B: Specimen and load device stabilized at agreed temperature/RH, after 24 h the load is applied and measurements taken (H4 at 60 ± 10 s; subsequent H values at chosen intervals).
Recommended test conditions include temperatures (23, 40, 60, 80, 100, 120, 140 ± 2 °C), stresses (10–150 kPa ± 5 %), humidities (0–5 %, 50 %, 90 ± 5 % or ambient) and times (1, 2, 7, 14, 28 days ± 5 %).

Calculations and reporting

Initial deformation (%) and compressive creep (%) are calculated from measured thicknesses. Test reports must list specimen identification, dimensions, skin type (if any), test mode (A or B), load, temperature, RH, duration, and results.

Notes on accuracy

Interlaboratory data are not available; repeatability and accuracy are therefore not established in the standard.

Applications and Users

ISO 7850 is used for:

Material selection and quality control of rigid cellular plastics (thermal insulation, sandwich cores, packaging foam).

Product specification, comparative testing, and accelerated aging evaluation. Primary users: materials engineers, QA/test laboratories, foam manufacturers, building-product developers, and research organizations.

SIST ISO 7850:1996 PDF

Abstract

Похожие стандарты

Overview

Key Topics and Requirements

Applications and Users

Related Standards

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ISO 7850:1986

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