Changes in the design, construction and contents of buildings have created a built environment which is in many ways more complex and hazardous in the event of fire.
Mae newidiadau o ran dyluniad, adeiladwaith a chynnwys adeiladau wedi creu amgylchedd adeiledig sydd, mewn sawl ffordd, yn fwy cymhleth a pheryglus yn achos tân.