FAQ's - Whitehouse Scientific

What colour are the glass beads?

Most of our particle size reference standards are transparent in nature. Our opaque materials are specific to Laser Diffraction.

What are the glass beads made of?

Soda-Lime Glass. The technical specification / chemical composition can be found in the 'Literature' section of our website.

What shape are the glass beads?

The majority of beads are spherical with a shape factor of 1. However, due to the production process some beads will have a shape factor extending to approximately 1.2

What is the density of Soda Lime Glass?

2.5 g/cm3. The technical specification / chemical composition can be found in the 'Literature' section of our website.

What is the Refractive Index of the glass beads?

1.46. The technical specification / chemical composition can be found in the 'Literature' section of our website.

What does ‘NIST Traceable’ mean?

NIST is the National Institute of Standards and Technology, a unit of the U.S. Commerce Department. Formerly known as the National Bureau of Standards, NIST promotes and maintains measurement standards. Using a NIST standard (e.g. Microscope calibration graticule) enables one to perform microscope and image analysis length measurements so that results are directly traceable back to NIST through a recognised auditable documentation trail.

What is a Polydisperse standard?

A particle size standard that consists of a range of different sized particles.

What is a Monodisperse standard?

A particle size standard that consists of identical or very similar sized particles. They can also be referred to as 'Monospheres'.

Why are the beads sold in different weights?

Beads are sold in one-shot bottles and not all techniques and instruments use the same weight of product. A wide range of weights enables you to select the correct one-shot weight appropriate to your specific application.

Are the plastic bottles reusable?

No. To avoid cross contamination with another material, the bottles should remain as single use.

Can the plastic bottles be recycled?

Yes, please refer to your local recycling conditions.

Can I take a sub-sample out of a bottle?

No. Any sub-sample taken may not be representative of the original bulk and erroneous results may be observed. The certificate will be invalidated by sub-sampling.

Can I re-use material?

No. When you have used a standard once, then it would be impossible to collect all the original particles. Therefore its original distribution may have been compromised by either a loss of material or contamination and should not be re-used. The certificate will be invalidated by continued re-use.

In the case of Sieve Standards over 1mm in size, re-use is permitted provided losses are kept below 3% of original weight.

My sieves are larger than 200mm diameter,
how much Sieve Calibration Standard should I be using?

200mm = 1 bottle
300mm = 2 bottles
450mm = 5 bottles
1000mm* = 10 bottles
2000mm** = 20 bottles

* For a 1000mm sieve, 10 bottles equals approximately 30% coverage of the sieve surface as opposed to our usual 80%. This is sufficient in these circumstances, however, it is recommended 3 tests are performed by the operator to ensure good repeatability of the test.
Alternatively, in order to cover 80% of the sieve surface, 25 bottles should be used.

** For a 2000mm sieve, 20 bottles equals approximately 30% coverage of the sieve surface as opposed to our usual 80%. This is sufficient in these circumstances, however, it is recommended 3 tests are performed by the operator to ensure good repeatability of the test.
Alternatively, In order to cover 80% of the sieve surface, 100 bottles would be required.

Are you accredited to ISO9001

Yes. ISO9001-2015.

Are you accredited to ISO17025

No. Whitehouse Scientific works to the 'principals of ISO17025' and has a full audit trail and supporting documentation to prove this claim.

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