ISO 8655-5:2022 – A New Standard for Dispensers
If you work in a laboratory that uses piston-operated volumetric apparatus (POVA), such as pipettes, burettes, dilutors, dispensers, and syringes, you may have heard of the new revision of the ISO 8655 standard. This standard specifies the terminology, general requirements, and user recommendations for POVA, as well as the metrological and performance requirements, test methods, and calibration procedures for each type of POVA.
In this article, we will focus on one part of the ISO 8655 standard, namely ISO 8655-5:2022, which applies to dispensers. We will explain what this standard is, what are the main changes from the previous version, what are the benefits and applications of this standard, how to comply with this standard, and where to find ISO 8655-5 pdf free download.
What is ISO 8655-5:2022?
Definition and scope of the standard
ISO 8655-5:2022 is an international standard that specifies:
- the metrological requirements for dispensers,
- the maximum permissible errors for dispensers,
- the requirements for marking and information to be provided for users for dispensers.
It is applicable to dispensers with nominal volumes from 1 μl up to 200 ml, designed to deliver their volume (Ex). A dispenser is defined as a POVA that delivers a series of equal volumes without refilling.
Main changes from the previous version
This second edition cancels and replaces the first edition (ISO 8655-5:2002), which has been technically revised. It also incorporates the Technical Corrigendum ISO 8655-5:2002/Cor.1:2008. The main changes are as follows:
- ISO 8655-7 and ISO 8655-8 have been added as normative references,
- the terms “calibration” and “test” have been defined and distinguished,
- the reference measurement procedures have been updated and clarified,
- an alternative measurement procedure has been introduced,
- the tolerances for the system of POVA and tip have been specified,
- the user information has been expanded.
Benefits and applications of the standard
The purpose of ISO 8655-5:2022 is to ensure the accuracy, precision, reliability, and traceability of dispensers used in laboratories. By complying with this standard, users can:
- improve the quality and consistency of their measurements,
- reduce the risk of errors and uncertainties,
- increase their confidence and credibility,
- satisfy the requirements of accreditation bodies and regulators,
- facilitate the comparison and compatibility of results.
Dispensers are widely used in various fields of science, such as chemistry, biology, medicine, pharmacy, environmental analysis, food testing, etc. They are especially useful for dispensing small volumes of liquids with high accuracy and repeatability.
How to comply with ISO 8655-5:2022?
Metrological requirements and maximum permissible errors
The metrological requirements for dispensers are based on the concept of the accuracy of the dispensed volume and the maximum permissible errors (MPE) for dispensers. The MPE depend on the nominal volume, the selected volume, and the number of dispenses. The MPE are given in Table 1.
| Nominal volume (μl) | Selected volume (μl) | Number of dispenses | MPE (μl) |
|---|---|---|---|
| 1 | 1 | 1 | ±0.15 |
| 10 | 10 | 1 | ±0.30 |
| 100 | 100 | 1 | ±0.60 |
| 1000 | 1000 | 1 | ±3.00 |
| 5000 | 5000 | 1 | ±15.00 |
| 10000 | 10000 | 1 | ±30.00 |
| 10 or more | ±15.00 or ±0.15% of the total dispensed volume, whichever is greater. | ||
| 20000 or more | 20000 or more | 1 or 2 | ±60.00 or ±0.30% of the total dispensed volume, whichever is greater. |
| 3 or more | ±30.00 or ±0.15% of the total dispensed volume, whichever is greater. |
Adjustment and calibration methods
To ensure that the dispensers meet the MPE, they need to be adjusted and calibrated regularly. Adjustment is the process of modifying the dispensing system to correct any deviation from the nominal or selected volume. Calibration is the process of determining the actual dispensed volume and comparing it with the nominal or selected volume.
The standard ISO 8655-5:2022 specifies two methods for adjustment and calibration of dispensers: the reference measurement procedure and the alternative measurement procedure.
The reference measurement procedure is based on gravimetric analysis, which involves weighing the dispensed liquid on an analytical balance and converting the mass to volume using the density of water at a given temperature and pressure. This procedure requires a reference balance with a minimum resolution of 0.01 mg for nominal volumes up to 100 μl, 0.1 mg for nominal volumes up to 1000 μl, and 1 mg for nominal volumes above 1000 μl.
The alternative measurement procedure is based on photometric analysis, which involves measuring the absorbance of a colored solution dispensed into a cuvette and converting the absorbance to volume using a calibration curve. This procedure requires a reference photometer with a wavelength range of 400 nm to 800 nm and a resolution of 0.001 absorbance units.
User information and marking
The standard ISO 8655-5:2022 also specifies the requirements for user information and marking for dispensers. The user information should include:
- a description of the dispenser and its components,
- a statement of conformity with ISO 8655-5:2022,
- a declaration of metrological traceability,
- a certificate of performance with the results of adjustment and calibration,
- a user manual with instructions for operation, maintenance, cleaning, decontamination, storage, and disposal.
The marking should include:
- a manufacturer’s name or trademark,
- a serial number or identification code,
- a nominal volume or volume range,
- a minimum graduation or increment,
- a symbol indicating compliance with ISO 8655-5:2022.
Where to find ISO 8655-5:2022 pdf free download?
Official sources and purchase options
The official source for ISO standards is the International Organization for Standardization (ISO) website, where you can find information about ISO 8655 -5:2022 and other related parts. You can also purchase the standard in PDF or hardcopy format from the ISO store or from your national standards body. However, ISO standards are not free and you may have to pay a significant amount to access them. For example, the price of ISO 8655-5:2022 in PDF format is 88 Swiss francs, which is equivalent to about 96 US dollars.
Preview and sample pages
If you are not sure whether you want to buy the standard or not, you can preview some sample pages from the ISO website. You can see the table of contents, the foreword, the introduction, and some excerpts from the main clauses of the standard. However, the preview is not complete and you cannot see the full text of the standard or the annexes. You also cannot download or print the preview pages.
Alternative sources and risks
You may be tempted to look for alternative sources that offer ISO 8655-5:2022 pdf free download, such as file-sharing websites, online forums, or social media groups. However, we strongly advise you against doing so for several reasons: – The quality and authenticity of the downloaded files may be compromised. You may end up with a corrupted, outdated, incomplete, or fake version of the standard that does not reflect the official content and requirements. – The security and legality of the downloaded files may be questionable. You may expose your device to malware, viruses, or spyware that can harm your data and privacy. You may also violate the intellectual property rights of ISO and its members and face legal consequences. – The reliability and availability of the downloaded files may be uncertain. You may encounter broken links, expired files, or restricted access that prevent you from downloading or opening the files. You may also lose the files if you delete them accidentally or if your device crashes. Therefore, we recommend that you use only official sources and purchase options for ISO 8655-5:2022 pdf free download. This way, you can ensure that you get the most accurate, updated, and trustworthy version of the standard that meets your needs and expectations.
Conclusion
In conclusion, ISO 8655-5:2022 is a new standard for dispensers that specifies the metrological requirements, maximum permissible errors, marking, and user information for this type of POVA. It also provides two methods for adjustment and calibration of dispensers: the reference measurement procedure and the alternative measurement procedure.
Complying with this standard can help users improve their measurement quality, reduce their error risk, increase their confidence and credibility, satisfy their accreditation and regulatory requirements, and facilitate their result comparison and compatibility.
To access this standard, users can purchase it in PDF or hardcopy format from the ISO website or from their national standards body. They can also preview some sample pages from the ISO website. However, they should avoid using alternative sources that offer ISO 8655-5:2022 pdf free download as they may pose quality, security, legality, reliability, and availability issues.
FAQs
What is a dispenser?
A dispenser is a POVA that delivers a series of equal volumes without refilling.
What is the difference between calibration and adjustment?
Calibration is the process of determining the actual dispensed volume and comparing it with the nominal or selected volume. Adjustment is the process of modifying the dispensing system to correct any deviation from the nominal or selected volume.
What are the maximum permissible errors for dispensers?
The maximum permissible errors for dispensers depend on the nominal volume, the selected volume, and the number of dispenses. They are given in Table 1.
What are the two methods for adjustment and calibration of dispensers?
The two methods for adjustment and calibration of dispensers are the reference measurement procedure and the alternative measurement procedure. The reference measurement procedure is based on gravimetric analysis, while the alternative measurement procedure is based on photometric analysis.
Where can I find ISO 8655-5:2022 pdf free download?
You can find ISO 8655-5:2022 pdf free download from the ISO website or from your national standards body, but you have to pay for it. You can also preview some sample pages from the ISO website for free. However, you should not use alternative sources that offer ISO 8655-5:2022 pdf free download as they may be unreliable, unsafe, illegal, or inaccurate.
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