ACI Environmental & Worker Safety 2

Question 1

What is the OSHA permissible exposure limit (PEL) for respirable crystalline silica over an 8-hour shift?

Accepted Answer

0.05 mg/m³

Answer

OSHA's PEL for respirable crystalline silica is 0.05 mg/m³ as an 8-hour time-weighted average.

Question 2

When working with concrete in hot weather, which condition most increases the risk of heat stroke for finishers?

Accepted Answer

High humidity combined with high temperature

Answer

High humidity prevents sweat from evaporating effectively, reducing the body's ability to cool itself and dramatically increasing heat stroke risk.

Question 3

Which type of respirator provides the highest level of protection against concrete dust containing silica?

Accepted Answer

N95 filtering facepiece

Answer

An N95 respirator filters at least 95% of airborne particles and is the minimum NIOSH-approved option recommended for silica dust exposure.

Question 4

Concrete washout water is classified as what type of waste requiring proper disposal?

Accepted Answer

Alkaline hazardous waste

Answer

Concrete washout water has a very high pH (11–13) and is classified as an alkaline hazardous waste that must not be discharged to storm drains.

Question 5

What does the SDS (Safety Data Sheet) Section 8 specifically address?

Accepted Answer

Exposure controls and personal protective equipment

Answer

SDS Section 8 covers exposure controls including OELs, engineering controls, and required PPE for safe handling.

(ACI) American Concrete Institute Concrete Finisher Practice Test