Construction Skills Certification Scheme (CSCS) Practice Test 2025 – All-in-One Guide to Master Your Certification Exam!

The appropriate answer highlights that both naked flames and sparks can act as ignition sources for flammable vapours.

Naked flames, such as those from matches or lighters, produce high temperatures and direct fire, which can ignite flammable vapours in the air. When volatile substances evaporate and mix with air in the right proportions, these vapours can become highly combustible. A naked flame poses a significant risk as it can easily ignite these vapours when they come into contact with it.

Sparks also represent a serious ignition hazard. They can be generated from various sources, such as electrical equipment malfunction, friction, or metal tools striking one another. When these sparks land on or near flammable vapours, they can generate enough heat to cause ignition, leading to combustion.

The combination of naked flames and sparks being capable of igniting flammable vapours emphasizes the importance of stringent safety measures on construction sites and other settings where such vapours might be present. Proper ventilation, removal of ignition sources, and the use of non-flammable materials are crucial to prevent hazardous situations.