Hot Water Insoluble Nitrogen 
The percentage of insoluble nitrogen fertiliser content (in urea formaldehyde or methylene urea products) which results from being placed in water at a temperature of 100°C for 30 minutes. (BS ISO 19670: 2017)
Hot Water Insoluble Nitrogen
The percentage of insoluble nitrogen fertiliser content (in urea formaldehyde or methylene urea products) which results from being placed in water at a temperature of 100°C for 30 minutes. (BS ISO 19670: 2017)