Supporting exposed insulation above exposed sprinklers

02 May 2019

Masterspec has received advice, via a subscriber, from a sprinkler system certifier concerned with the installation of non self-supporting insulation when positioned above or in close proximity to exposed sprinkler heads, particularly in a roof/ceiling situation.

Where exposed flexible non-supporting insulation is installed at roof level above a ceiling, the effects of its sagging needs to be considered to ensure concealed space fire sprinkler head coverage is not compromised.  Practice Note NFPA13 A8.5.4.1 states, in part, "… and attached to the ceiling/roof in such a manner that it will not fall out during a fire prior to sprinkler activation".

It is noted that plastic strapping commonly used is insufficient to prevent flexible insulation sagging during a fire prior to sprinkler activation, due to plastics losing their structural integrity at relatively low temperatures.  Also, it is not considered a good long-term solution to tightly pack insulation into the space to omit the need for specific support.  Likewise, when exposed insulation is installed above walls from ceiling to floor/roof, it may need support to prevent collapse during a fire onto the ceiling space sprinklers.  Ideally, they need to be spaced far enough away to prevent collapsed insulation obstructing the sprinkler heads.

Masterspec has reviewed the insulation work sections (25 in total) and added standard clauses (or in some cases updated existing clauses).  As a result, the plastic strapping tape clauses have been updated to include reference to NZBC E2/AS1 which covers requirements for stud spacing for drained cavities. Also, when exposed insulation is over exposed sprinkler heads it is recommended that galvanized wire or wire netting insulation support be provided to avoid the risk of a fire event affecting the sprinkler head's performance.

Finally, wire netting clauses have been added or updated to cover roof / ceiling situations where wire netting is installed over purlins or under joists / purlins, to support flexible non self-supporting insulation.

For further information refer to the appropriate insulation work section.