Self-Heating Solids – UN Test N.4 Testing
Our UK laboratory generates test data for materials that you are looking to transport. The Self Heating Solids – UN Test N.4 is conducted for the purposes of transportation testing for self-heating properties of bulk materials
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Frequently asked questions
What are your Standards & Schedule of Accreditation?
Recommendations on the Transport of Dangerous Goods, UN Manual of Test & Criteria – UN Test N.4
What is the Self Heating Solids – UN Test N.4 Test?
The test is conducted to determine whether a solid material should be classified as a Self-Heating Solid of UN Class 4, Division 4.2. The same test technique applies to classification under CLP as a Self-Heating Solid (H.251 & H.252)
How does the Self Heating Solids – UN Test N.4 Test work?
The sample, in its commercial form, is filled to the brim of the test basket and the basket is tapped several times. More material is added, if the material is seen to have settled. The test basket is housed in a wire mesh cover and placed into the centre of a preheated, hot air, circulating oven, set to the required test temperature.
The initial test is conducted using a 100 mm basket, at a temperature of 140 °C. The sample temperature and oven temperature are continually monitored, using inconel sheathed thermocouples over a test period of 24 h (unless ignition is detected earlier). If ignition is not observed, then the material is not classified as a self-heating solid. If ignition is observed, then the material is classified, and further testing is required to designate the correct packing group and/or define the classification exemption conditions.
How can UN Test N.4 data help?
Although the material may be a self-heating substance, if transported within specified volume restrictions, exceptions can be made and therefore huge costs are avoided. These exemptions can only be determined through testing.