Analytisk kemi

This document is a product specification, giving minimum performance requirements for non plumbed-in emergency safety eyewash units. It is applicable to non plumbed-in emergency safety eyewash units filled by the manufacturer with a washing fluid that can be either water or solutions for first aid use when the eyes have been exposed to harmful substances. Requirements are also given concerning labelling, marking and information to be supplied by the manufacturer.

This document is a product specification, giving minimum performance requirements for non plumbed-in emergency safety body showers. It is applicable to body showers filled by the manufacturer with a washing fluid that can be either water or solutions, and to empty devices to be filled prior to putting into service. Both variations are for first aid use when the body or parts of the body have been exposed to harmful substances or heat. Requirements are also given concerning labelling, marking and information to be supplied by the manufacturer.

This document establishes the requirements for the purity analysis of materials used in the preparation of calibration gas mixtures and the use of these purity data in calculating the composition of the mixture thus prepared.

ISO 6145 is a series of documents dealing with various dynamic methods used for the preparation of calibration gas mixtures. This document specifies a method for continuous preparation of calibration gas mixtures, from nominally pure gases or gas mixtures by use of thermal mass-flow controllers. The method is applicable to preparation of mixtures of non-reacting species, i.e. those which do not react with any material of construction of the flow path in the thermal mass-flow controller or the ancillary equipment.

If this method is employed for preparation of calibration gas mixtures the optimum performance is as follows: the relative expanded measurement uncertainty U, obtained by multiplying the standard uncertainty by a coverage factor k = 2, is not greater than 2 %.

If pre-mixed gases are used instead of pure gases, mole fractions below 10−6 can be obtained. The measurement of mass flow is not absolute and the flow controller requires independent calibration.

The merits of the method are that a large quantity of the calibration gas mixture can be prepared on a continuous basis and that multi-component mixtures can be prepared as readily as binary mixtures if the appropriate number of thermal mass-flow controllers is utilized.

NOTE Gas blending systems, based upon thermal mass-flow controllers, and some including the facility of computerization and automatic control, are commercially available