The current standard for mortar is I.S. EN 998-1 :2012 Specification for mortar for masonry.
The sand used to produce mortar should comply with the requirement of SR 18, Guidance on the use of I.S. EN13139:2002 - Aggregates for mortar. The SR gives the NPD’s (National defined parameters) for the PSD (particle size distribution) and chemical requirements of the sands used to produce mortar.
Mortar strength is now specified as a compressive strength class i.e. M6, the number following the M is the compressive strength for the class at 28days in N/mm²
Table NA.3 below is taken from the Irish National Annex to Eurocode 6 - Design of masonry structures - Part 1-1: General rules for reinforced and unreinforced masonry structures
The table gives new compressive strength class, proportions and the old Mortar designation.
Mortar is available from Roadstone as TRM ( trowel ready mortar) or Flowmix (dry silo mortar)
Technical Certification & Declaration of Performance (DOP) are available to download - just click here.