BS ISO 18642:2016 pdf download – Fertilizer and soil conditioners — Fertilizer grade urea — General requirements
1 Scope
This International Standard specifies the general requirements regarding testing methods, sampling and preparation of test sample, marking and labelling, package, transport, and storage of fertilizer grade urea.
This International Standard is applicable to urea in solid form, e.g. granular, prilled, or pastilled, which is made by the reaction of ammonia with carbon dioxide. Urea can be classified by its intended use,industrial and/or agricultural. It is mainly used as fertilizer in the field of agriculture. This International Standard is only applicable to fertilizer grade urea in the field of agriculture.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5315, Fertilizers — Determination of total nitrogen content — Titrimetric method after distillation
ISO 7410, Fertilizers and soil conditioners — Final samples — Practical arrangements
ISO 7742:1988, Solid fertilizers — Reduction of samples
ISO 8397, Solid fertilizers and soil conditioners — Test sieving
ISO 8633, Solid fertilizers — Simple sampling method for small lots
ISO 18643, Fertilizers and soil conditioners — Determination of biuret content of urea-based fertilizers — PLC method
EN 13466-1:2001, Fertilizers — Determination of water content — (Karl Fischer methods) — Part 1: Methanol as extracting medium
3Terms and definitions
For the purposes of this document, the following terms and definitions apply.
white crystalline, or granular, or prill, or pastill, solid synthesized from ammonia and carbon dioxide under high temperature and pressure by a number of processes
Note 1 to entry: The molecular formula is CO(NH 2 ) 2 . The molecular weight is 60,053 according to IUPAC’s 2011 report on standard atomic weights.
[SOURCE: ISO 8157:2015,, modified — In the definition, “or prill, or pastill,” has been added. Note 1 to entry has been added.]
4 Requirement
4.1 Appearance: The product shall be solid, such as in granular or prilled or pastill form, generally white in colour.
4.2 Fertilizer grade urea products shall be tested to demonstrate conformance with all the requirements specified in Table 1.
5 Testing methods
5.1 Appearance
Visually inspect for the presence of contaminant and foreign matter.
5.2 Determination of total nitrogen contents
Nitrogen contents shall be determined in accordance to ISO 5315.
NOTE EN 15478:2009 and AOAC 993.13:1996 are similar in principle to ISO 5315.
5.3 Determination of biuret content
Biuret content shall be determined according to ISO 18643.
5.4 Determination of moisture (H 2 O) content
Moisture (H 2 O) content shall be determined according to EN 13466-1:2001.
5.5 Determination of particle sizes
Particle sizes shall be determined according to ISO 8397.
6 Sampling and preparation of test sample
6.1 Sampling method
6.1.1 Products in bags
Carry out sampling operation by following the procedure described in ISO 8633. Care should be taken to avoid damage to the particles.
6.1.2 Products in bulk
Carry out sampling operation by following the procedure described in ISO 8633.
6.2 Reduction of samples
Mix all the increments (collected as in 6.1) uniformly and promptly to form a single aggregate sample using a device or by hand. The aggregate sample is reduced to about 1 kg by the riffle sample divider method (see ISO 7742:1988, A.2) or the quartering method (see ISO 7742:1988, A.3). Next, divide into two parts for final laboratory samples. The two laboratory samples are put into two clean and dry glass or plastic containers or any other inert material of adequate resistance capable of maintaining the sample in its original condition. The containers shall be fitted with airtight closures. Carry out all the operations described earlier as rapidly as possible to avoid loss or gain of moisture. Each container shall be secured and sealed following the instruction given in ISO 7410. Each laboratory sample shall be labelled following the instructions given in ISO 7410. The label shall, at minimum, carry the following information:
a) the name of manufacturer;
b) the name of product and type;
c) the manufacturer’s reference and batch number or production date (if available);
d) the lot size;