No. 527 August 2007 

The Partial Cab: A New Noise Engineering Control for Surface Drill Rigs 

Objective 

The National Institute for Occupational Safety and 

Health (NIOSH), in partnership with stakeholders in 

the mining and surface drilling industries, conducted research to develop engineering control technologies that reduce workplace noise exposure. The 

result of this research partnership is the development 

of a partial cab. 

Background 

Noise-induced hearing loss (NIHL) continues to 

be an occupational health problem in the U.S. mining 

industry. Hearing loss data suggest that by age 50, 

nearly 90% of coal miners have a hearing impairment. 

This compares to 10% for a general population of 

nonexposed males. Previous studies showed that 

operators of noncab surface drill rigs are overexposed 

to noise. These rigs are used in various surface drilling industries, including mining and construction. 

Many surface rigs do not have full cabs as a result of 

the original equipment manufacturer design or the 

prohibitive cost of aftermarket products. 

Approach 

Engineering controls are the most desirable among 

the hierarchy of controls to lower noise exposure and 

prevent NIHL. NIOSH researchers determined that a 

noise control to protect the operator at the rig’s 

control panel would be effective based on the 

organization of work practices and typical worker 

behaviors. As a result, researchers developed the partial cab (Figure 1). 

Figure 1.—The partial cab is retrofitted to the air rotary drill rig 

with a steel frame. The cab slides on a heavy-duty linear rail that 

supports the weight of the cab, allows for easy operation, and This resists wear. engineering control design 

addressed stakeholders’ needs associated with cost, 

transport, and worker usage. Field tests found the partial cab effective in reducing noise exposure at the 

rig’s control panel, a typical location for a drill rig 

operator (Figure 2). In one case, sound levels at the 

control panel were reduced from 104 to 96 dB(A). 

Coupled with continued use of personal protective 
equipment such as hearing protection devices, the 

partial cab can help reduce noise exposures below the 

NIOSH recommended exposure limit (85 dB(A)) during a typical workday. 

Figure 2.—In the field, the sound level at the operator’s station 

without the partial cab was over 100 dB(A) during hammer drilling. 

The partial cab reduced the sound levels by 5–9 dB(A). 

Partial Cab Communication Suite 

A communication suite (DHHS (NIOSH) Publication No. 2007–147c) was assembled with multiple 

information components to help surface drilling operators understand the benefit of this noise control 

technology, as well as how to construct the partial cab. The suite is packaged on a CD to be viewed 

on a standard computer and includes video, graphic, 

and instructive components. For example, a viewer of 

the CD can watch a video that highlights the benefits 

of the partial cab in real work scenarios, view CAD 

drawings of the partial cab design, and then print out 

information on construction materials and design 

details. The CD also provides background information on NIHL and hearing protection devices to 

increase knowledge about this occupational health 

concern. This information can be coupled with an 

accompanying training checklist to help promote the 

partial cab’s importance to workers using the 

technology. 

For More Information 

The Partial Cab Communication Suite is available 

through NIOSH at http://www.cdc.gov/niosh/mining/ 

pubs or through the National Ground Water Association at http://www.ngwa.org 

For more information on partial cabs for reducing 

noise exposure, contact David S. Yantek, NIOSH 

Pittsburgh Research Laboratory, P.O. Box 18070, 

Pittsburgh PA 15236–0070; phone: (412) 386–4498; 

e-mail: DYantek@cdc.gov. 

To receive NIOSH documents or for more information about occupational safety and health topics, 

contact: 1–800–CDC–INFO (1–800–232–4636), 

1–888–232–6348 (TTY), e-mail: cdcinfo@cdc.gov, 

or visit the NIOSH Web site at http:// 

www.cdc.gov/niosh 

Mention of any company name or product does not 

constitute endorsement by the National Institute 

for Occupational Safety and Health. 

DHHS (NIOSH) Publication No. 2007–153