4 Reasons to Use Permeation Tubes instead of Gas Cylinders

Safety

• Permeation tubes contain a tiny fraction of the amount of analyte present in cylinders. This means that in the event of exposure to dangerous compounds, the potential harm is greatly reduced.
• High pressure cylinders are inherently dangerous. Upon rupturing, they can travel at speeds of 170mph, and can cause injury or even death (see HSE press release for more details). Even when structurally intact, cylinders can be very heavy, and must be securely fastened to walls to prevent them from causing injury by falling.

Economy

• Permeation Tubes have significantly longer lifetimes (up to 2 years) than gas cylinders, especially for corrosive compounds such as HF.
• Permeation tubes allow hundreds of different analytes to be stored in the space needed for just one gas cylinder, freeing up laboratory space.
• Taking into consideration purchase, storage and disposal costs, permeation tubes offer significant costs savings when compared with gas cylinders, typically within 2 years of use.

Practicality

• Polar and/or highly reactive analytes interact with the walls of gas cylinders, causing the concentration to continuously drop. Permeation tubes produce a reliable concentration, even for these kinds of molecules.
• It is straightforward to produce humidified mixtures by simply running a humidified makeup flow around the permeation tube. Owlstone’s OHG humidity generator can be mounted in the GEN-SYS rack alongside the OVG-4 calibration gas generator to provide an integrated system for producing humidified mixtures.
• Permeation tubes mean setting up experiments, and changing between different mixtures, can be achieved much more quickly – it takes seconds to switch one permeation tube for another in the OVG-4.

Accuracy

• The OVG-4 system can produce concentrations in the ppm to ppb region, with an accuracy around ±2%
• Owlstone’s permeation tubes are traceable to NIST/UKAS standards, and come with their own calibration certificates.