HOME   Cart(0)   Quotation   About-Us Policy PDFs Standard-List
www.ChineseStandard.net Database: 189760 (18 Oct 2025)

GB/T 42999-2023 PDF English

US$165.00 · In stock · Download in 9 seconds
GB/T 42999-2023: Home textiles - Determination of the light blocking effect of fabric - Illuminometer method
Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedure
Status: Valid
Standard IDContents [version]USDSTEP2[PDF] deliveryName of Chinese StandardStatus
GB/T 42999-2023English165 Add to Cart 0-9 seconds. Auto-delivery Home textiles - Determination of the light blocking effect of fabric - Illuminometer method Valid

Excerpted PDFs (Download full copy in 9 seconds upon purchase)

PDF Preview: GB/T 42999-2023
      

Similar standards

GB/T 38880   GB/T 22799   GB/T 32610   GB/T 31128   

GB/T 42999-2023: Home textiles - Determination of the light blocking effect of fabric - Illuminometer method


---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT42999-2023
GB NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 59.080.30 CCS W 55 GB/T 42999-2023 Home textiles - Determination of the light blocking effect of fabric - Illuminometer method ISSUED ON: SEPTEMBER 7, 2023 IMPLEMENTED ON: APRIL 01, 2024 Issued by: State Administration for Market Regulation; Standardization Administration of the People’s Republic of China.

Table of Contents

Foreword ... 3 1 Scope ... 4 2 Normative references ... 4 3 Terms and definitions ... 4 4 Principle ... 5 5 Test method ... 5 6 Test report ... 7 Bibliography ... 9 Home textiles - Determination of the light blocking effect to fabric - Illuminometer method

1 Scope

This document describes the test method for determination of the light blocking effect to fabric using an illuminometer. This document applies to home textile fabrics and their products.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 6529 Textiles - Standard atmospheres for conditioning and testing

3 Terms and definitions

For the purpose of this document, the following terms and definitions apply. 3.1 light blocking effect The ability of textiles to prevent the transmission of light. NOTE: It is expressed as blocking rate. 3.2 illuminance The quotient of the luminous flux incident on the surface element containing the point divided by the area of the surface element. NOTE: The unit is lux (lx). [Source: GB 50034-2013, 2.0.6, modified]

4 Principle

Irradiate stable light with a certain intensity on the surface of the sample, measure the illuminance after the light passes through the sample, compare it with the illuminance without the sample, and characterize the light blocking effect of the fabric by calculating the light blocking rate of the sample.

5 Test method

5.1 Test apparatus 5.1.1 The light blocking effect test apparatus shall include: a test chamber for placing the sample, with a round hole in the center of the top; a light source simulating sunlight is placed directly above the test chamber and vertically corresponding to the round hole of the test chamber; an illuminometer is placed at the bottom of the test chamber to measure changes in illuminance. Figure 1 shows a schematic diagram of a light blocking effect test apparatus. Other apparatuses with the same effect can also be used. 5.1.2 Test chamber: The size is approximately 40 cm × 40 cm × 10 cm. The diameter of the round hole at the top that exposes the sample to the light source shall be 10 cm. The internal surface of the test chamber shall be covered with black coating material to avoid light reflection inside the chamber that will affect the test results. 5.1.3 Light source: Halogen lamp, the illuminance can reach up to 199000 lx, installed on a height-adjustable shelf. 5.1.4 Illuminometer: It shall be located at the center position below the round hole of the test chamber. The test range is 0.01 lx ~ 199000 lx. The measurement accuracy of the illuminometer is ±2 %. 5.4 Test procedures 5.4.1 Turn on the power switch of the test apparatus and the power indicator light will light up. 5.4.2 Calibrate the illuminometer. 5.4.3 Set the illuminance of the light source. Set the illuminance of the light source of the apparatus to 100000 lx, and read the illuminance value (i0) in this state. 5.4.4 Measure the illuminance value of the sample. Place the sample on the upper part of the apparatus, with the test surface facing the light source, the surface of the sample is flat and wrinkle-free, and read the illuminance value (i1) passing through the sample. 5.5 Result calculation 5.5.1 Calculate the blocking rate (%) according to formula (1). The test result is the average of three samples, rounded to single digits. where: T - the blocking rate, %; i1 - the illuminance value after installing the sample, in lux (lx); i0 - the illuminance value when the sample is not installed, in lux (lx). 5.5.2 For homogeneous samples, use the average of three samples as the test result; for samples with different colors or fabric structures, report the average of the test results for each color or structure.

6 Test report

The test report shall include the following content: a) Indicate that the test is conducted in accordance with this document; b) Description of the sample; c) Test temperature and relative humidity; d) If necessary, indicate the test surface of the sample; e) Test results; ......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.


      

Tips & Frequently Asked Questions

Question 1: How long will the true-PDF of English version of GB/T 42999-2023 be delivered?

Answer: The full copy PDF of English version of GB/T 42999-2023 can be downloaded in 9 seconds, and it will also be emailed to you in 9 seconds (double mechanisms to ensure the delivery reliably), with PDF-invoice.

Question 2: Can I share the purchased PDF of GB/T 42999-2023_English with my colleagues?

Answer: Yes. The purchased PDF of GB/T 42999-2023_English will be deemed to be sold to your employer/organization who actually paid for it, including your colleagues and your employer's intranet.

Question 3: Does the price include tax/VAT?

Answer: Yes. Our tax invoice, downloaded/delivered in 9 seconds, includes all tax/VAT and complies with 100+ countries' tax regulations (tax exempted in 100+ countries) -- See Avoidance of Double Taxation Agreements (DTAs): List of DTAs signed between Singapore and 100+ countries

Question 4: Do you accept my currency other than USD?

Answer: Yes. www.ChineseStandard.us -- GB/T 42999-2023 -- Click this link and select your country/currency to pay, the exact amount in your currency will be printed on the invoice. Full PDF will also be downloaded/emailed in 9 seconds.

How to buy and download a true PDF of English version of GB/T 42999-2023?

A step-by-step guide to download PDF of GB/T 42999-2023_EnglishStep 1: Visit website https://www.ChineseStandard.net (Pay in USD), or https://www.ChineseStandard.us (Pay in any currencies such as Euro, KRW, JPY, AUD).
Step 2: Search keyword "GB/T 42999-2023".
Step 3: Click "Add to Cart". If multiple PDFs are required, repeat steps 2 and 3 to add up to 12 PDFs to cart.
Step 4: Select payment option (Via payment agents Stripe or PayPal).
Step 5: Customize Tax Invoice -- Fill up your email etc.
Step 6: Click "Checkout".
Step 7: Make payment by credit card, PayPal, Google Pay etc. After the payment is completed and in 9 seconds, you will receive 2 emails attached with the purchased PDFs and PDF-invoice, respectively.
Step 8: Optional -- Go to download PDF.
Step 9: Optional -- Click Open/Download PDF to download PDFs and invoice.
See screenshots for above steps: Steps 1~3    Steps 4~6    Step 7    Step 8    Step 9