http://www.legislation.gov.uk/nisr/1999/91/regulation/3/made
Class Sizes in Primary Schools Regulations (Northern Ireland) 1999
Special educational needs and additional support
School welfare, behaviour and attendance
Primary schools
Government Printer for Northern Ireland
2015-07-23
EDUCATION
Article 16 of the Education (Northern Ireland) Order 1998 provides for a statutory limit to be prescribed by regulations on the number of pupils who may be in any class of pupils in Key Stage 1 of their compulsory education. It also provides for the Department to set out in those regulations the matters which education and library boards must have regard to when making exceptions to the class size limit.
Application3
These Regulations shall not apply in relation to any school year which begins before 1st August 1999.