Asphalt Pavement Magazine - November/December 2017 - 27

on June 23, 2018. Although the
Construction Standard applies to
roadway construction activities,
complying with General Industry
Standard obligations will require
asphalt mix production facilities to
review and mitigate sources of silica
exposure at plant sites.
For both the Construction and
General Industry standards, OSHA's
PEL is the same: 50 micrograms per
cubic meter (µm/m3), calculated
as an eight-hour time weighted
average, and the Action Level is
one-half the PEL, or 25 µm/m3.
This Action Level is the level of
exposure at which some of the
rule's compliance obligations
become applicable to an employer. If
activity-based exposures are below
the Action Level, there are minimal
obligations under the Standard.

Differences Between Standards
The Silica Rule standards are almost
identical for the construction
industry (i.e., industries
categorized under the NAICS 23
company code, including all road
construction activities) and general
industry activities, which include
manufacturing activities under the
NAICS 32 code, including asphalt
pavement mix production. The
biggest difference in compliance
obligations under the General
Industry and Construction
standards is that no pre-approved
exposure controls are offered under
the General Industry Standard.
Under the Construction
Standard, OSHA's Table 1
(http://goaspha.lt/2d7xzAH) outlines
common tasks and pre-approved
methods of ensuring compliance.
For example, using water
suppression and vacuum systems on
a co-planer milling machine.
Under the General Industry
Standard, OSHA requires an
assessment of "exposure for each
employee on the basis of any
combination of air monitoring
data or objective data sufficient to

accurately characterize employee
exposures to respirable crystalline
silica." This requirement is the same
under the construction standard for
activities without an approved Table
1 control.
Bottom line: Employers must
measure or know workers' activitybased silica exposures and, if
necessary, implement appropriate
exposure controls to reduce worker
exposure. A list of asphalt pavement
mix facility activities that may require
exposure assessment is provided as a
sidebar within this article.

General Industry Controls
The General Industry Standard
is clear that if worker exposure
is above the PEL, appropriate
measures must be taken to limit
silica exposure. The rule states under
29 CFR §1910.1053(f), Methods of
Compliance:
"(1) Engineering and work practice
controls. The employer shall use
engineering and work practice
controls to reduce and maintain
employee exposure to respirable
crystalline silica to or below the
PEL, unless the employer can
demonstrate that such controls
are not feasible. Wherever
such feasible engineering and
work practice controls are not
sufficient to reduce employee
exposure to or below the PEL,
the employer shall nonetheless
use them to reduce employee
exposure to the lowest feasible
level and shall supplement
them with the use of
respiratory protection that
complies with the requirements
of paragraph (g) of this section."
[emphasis added]
Given these requirements, it is
incumbent upon the employer to
understand activity-specific silica
exposure levels through direct
monitoring or objective data (see
sidebar) and to implement controls,
such as water suppression, which
continued on page 28

List of Asphalt
Facility Activities that
Generate Dust
As required under the Silica
Rule's General Industry Standard,
employers are required to
understand potential silicabearing dust exposures that
may be generated by activities
associated with asphalt mix
facilities. Because silica is inherent
in both aggregate and native soils,
any activity that creates dust can
potentially generate respirable
crystalline silica. The silica rule
requires identification of such
activities and assessment of its
exposure potential.
Listed below are asphalt
pavement mix facility activities
that may require exposure
assessment - either through direct
monitoring or identification of
objective data - to identify and
control sources of airborne silicaladen dust:
* Chipping/grinding/cleaning
material off mixing drum
flights and paddles
* Maintenance/repair inside
drying drum
* Handling of fines and
other baghouse maintenance
activities
* Screening or crushing RAP and/
or aggregate
* QA laboratory-based screening/
sieving activities
* Outdoor activities near or on
unpaved or gravel facility roads
and trails
* Cleaning inside aggregate
hoppers and bins
* Cleaning silos
* Cleaning conveyers
* Onsite sweeping or brooming
activities

Asphalt Pavement Magazine - November/December 2017 * 27


http://www.goaspha.lt/2d7xzAH

Table of Contents for the Digital Edition of Asphalt Pavement Magazine - November/December 2017

President’s Perspective
Industry News
Back to Basics: The Next Steps
Training for Safety
OSHA’s Silica Rule
How to Improve Safety Climate
Beyond the Horizon
Industry Calendar
Index of Advertisers/Advertisers.com
Asphalt Pavement Magazine - November/December 2017 - Intro
Asphalt Pavement Magazine - November/December 2017 - cover1
Asphalt Pavement Magazine - November/December 2017 - cover2
Asphalt Pavement Magazine - November/December 2017 - 3
Asphalt Pavement Magazine - November/December 2017 - 4
Asphalt Pavement Magazine - November/December 2017 - 5
Asphalt Pavement Magazine - November/December 2017 - 6
Asphalt Pavement Magazine - November/December 2017 - 7
Asphalt Pavement Magazine - November/December 2017 - 8
Asphalt Pavement Magazine - November/December 2017 - President’s Perspective
Asphalt Pavement Magazine - November/December 2017 - 10
Asphalt Pavement Magazine - November/December 2017 - 11
Asphalt Pavement Magazine - November/December 2017 - 12
Asphalt Pavement Magazine - November/December 2017 - Industry News
Asphalt Pavement Magazine - November/December 2017 - 14
Asphalt Pavement Magazine - November/December 2017 - 15
Asphalt Pavement Magazine - November/December 2017 - 16
Asphalt Pavement Magazine - November/December 2017 - Back to Basics: The Next Steps
Asphalt Pavement Magazine - November/December 2017 - 18
Asphalt Pavement Magazine - November/December 2017 - 19
Asphalt Pavement Magazine - November/December 2017 - Training for Safety
Asphalt Pavement Magazine - November/December 2017 - 21
Asphalt Pavement Magazine - November/December 2017 - 22
Asphalt Pavement Magazine - November/December 2017 - 23
Asphalt Pavement Magazine - November/December 2017 - 24
Asphalt Pavement Magazine - November/December 2017 - 25
Asphalt Pavement Magazine - November/December 2017 - OSHA’s Silica Rule
Asphalt Pavement Magazine - November/December 2017 - 27
Asphalt Pavement Magazine - November/December 2017 - 28
Asphalt Pavement Magazine - November/December 2017 - 29
Asphalt Pavement Magazine - November/December 2017 - 30
Asphalt Pavement Magazine - November/December 2017 - 31
Asphalt Pavement Magazine - November/December 2017 - How to Improve Safety Climate
Asphalt Pavement Magazine - November/December 2017 - 33
Asphalt Pavement Magazine - November/December 2017 - 34
Asphalt Pavement Magazine - November/December 2017 - 35
Asphalt Pavement Magazine - November/December 2017 - 36
Asphalt Pavement Magazine - November/December 2017 - 37
Asphalt Pavement Magazine - November/December 2017 - 38
Asphalt Pavement Magazine - November/December 2017 - 39
Asphalt Pavement Magazine - November/December 2017 - 40
Asphalt Pavement Magazine - November/December 2017 - 41
Asphalt Pavement Magazine - November/December 2017 - 42
Asphalt Pavement Magazine - November/December 2017 - 43
Asphalt Pavement Magazine - November/December 2017 - 44
Asphalt Pavement Magazine - November/December 2017 - 45
Asphalt Pavement Magazine - November/December 2017 - 46
Asphalt Pavement Magazine - November/December 2017 - 47
Asphalt Pavement Magazine - November/December 2017 - 48
Asphalt Pavement Magazine - November/December 2017 - 49
Asphalt Pavement Magazine - November/December 2017 - 50
Asphalt Pavement Magazine - November/December 2017 - 51
Asphalt Pavement Magazine - November/December 2017 - Beyond the Horizon
Asphalt Pavement Magazine - November/December 2017 - 53
Asphalt Pavement Magazine - November/December 2017 - Industry Calendar
Asphalt Pavement Magazine - November/December 2017 - 55
Asphalt Pavement Magazine - November/December 2017 - 56
Asphalt Pavement Magazine - November/December 2017 - Index of Advertisers/Advertisers.com
Asphalt Pavement Magazine - November/December 2017 - 58
Asphalt Pavement Magazine - November/December 2017 - cover3
Asphalt Pavement Magazine - November/December 2017 - cover4
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