NEBOSH CC Construction Site Hazards 2

Question 1

What is the most significant health risk from exposure to construction dust containing crystalline silica?

Accepted Answer

Silicosis (progressive fibrosis of the lungs)

Answer

Respirable crystalline silica (RCS) causes silicosis, an irreversible and progressive fibrotic lung disease. Construction activities such as cutting concrete, sandstone, granite, and mortar generate RCS dust. The UK workplace exposure limit is 0.1 mg/m3 (8-hour TWA). Silica exposure is also associated with lung cancer.

Question 2

A delivery lorry is reversing on a construction site. What is the most effective measure to prevent pedestrian being struck?

Accepted Answer

Segregation of vehicle and pedestrian routes with physical barriers

Answer

Physical segregation of vehicle and pedestrian routes is the most effective control measure, applying the hierarchy of control (engineering control). While reversing alarms, banksmen, cameras, and hi-vis clothing all help, they are lower-order controls that depend on human behaviour and can fail.

Question 3

Under the Electricity at Work Regulations 1989, what is the primary control measure to protect workers from contact with underground cables during excavation?

Accepted Answer

Use cable avoidance tools (CAT) and signal generator, plus safe digging practices

Answer

HSG47 guidance requires using cable avoidance tools (CAT scanner) and signal generators to locate underground services before excavation. Safe digging practices (hand digging within 500mm of detected services, no mechanical excavation near cables) must follow. Plans alone are unreliable as cables may have been diverted.

Question 4

A worker on a construction site develops occupational dermatitis from cement exposure. Which component of cement is primarily responsible for causing allergic contact dermatitis?

Accepted Answer

Hexavalent chromium (chromium VI)

Answer

Hexavalent chromium (Cr VI) in cement is the primary sensitiser causing allergic contact dermatitis. EU regulations limit Cr VI content in cement to 2 ppm (2 mg/kg). Cement also causes irritant contact dermatitis due to its high alkalinity (pH 12-13). Controls include reduced-chromate cement, gloves, and barrier creams.

Question 5

What is the purpose of a traffic management plan on a construction site?

Accepted Answer

To manage the safe movement of vehicles and pedestrians, minimising the risk of collisions

Answer

A traffic management plan (TMP) manages the safe movement of all vehicles and pedestrians on site. It should include designated routes, speed limits, one-way systems, turning areas, segregation of pedestrians, signage, banksmen requirements, and loading/unloading arrangements. It is a key requirement under CDM 2015.

NEBOSH Construction Certificate Practice Test

NEBOSH Construction Certificate Practice Test

NEBOSH CC Construction Site Hazards 2