For the working professional, it provides the "why" behind the "what" of the codes. The shift to full-color graphics and the rigorous treatment of modern hazards makes it a worthy successor to the NFPA legacy.
Here is a comprehensive review of its structure, content quality, relevance, and utility. Nfpa Fire Protection Handbook 21st Edition
includes new guidance on LIB thermal runaway. The handbook states that standard ABC dry chemical extinguishers are ineffective for LIB cells >200 Wh. Required agent mass for a 5 kWh pack is 35 lb of ABC (ineffective) vs. 3.5 gpm of water for cooling (effective per UL 2580). This contradicts firefighter instinct and is a critical update. For the working professional, it provides the "why"