Emergency Response Procedures for Ships Carrying Dangerous Goods (EmS Guide) states in its various schedules to use “copious quantities of water” for firefighting and handling spillage of dangerous goods.
For Example see fire schedule F-E below
“Copious quantities of water” means total quantities of water provided for optimal fire-fighting using four jets of water, as required by SOLAS regulation II-2/4.
IMDG Code Compliance Centre 