Evap testing at high altitude

Alan Stout Alan Stout to:

Frank Krich, james.ehlmann, Rudy, Sara (S.J.), 

susan.collet, Robert_Bienenfeld, klaus.land, 

Johnson, Stuart

05/09/2011 02:15 PM

Bcc: Alan Stout

Dear colleagues, 

We have been made aware that a recent change in the EPA regulations in §86.1810-09 

inadvertently changed the way we describe manufacturers’ responsibilities to comply with 

evaporative emission standards at high-altitude conditions. Our understanding is that the intent 

initially was to adopt California’s LEV II evaporative emission standards in the CFR, but only at 

low-altitude conditions, keeping the less stringent Tier 2 standards in place at high-altitude 

conditions. 

In the final rule adopting light-duty greenhouse gas standards, we addressed the altitude-related 

requirements in §86.1810-09 by restructuring paragraphs and rewording requirements in a way 

that eliminated evaporative emission standards at high-altitude conditions. This was not intended 

and, in fact, is contrary to other regulatory provisions (such as those in §86.1829-01). 

We plan to make this correction in the upcoming final rule related to fuel economy labels. The 

draft regulatory text to accomplish this is copied below. Given that the proposal for the labeling 

rule has already been published, we are eager to inform potentially affected parties that there is a 

need for this correction. Feel free to let us know if this approach raises any concerns.

On a separate and less time-sensitive note, we are pursuing a range of issues related to the 

upcoming Tier 3 rule. This correction gives us the opportunity to invite your input also on the 

proper approach to applying evaporative emissions at high-altitude conditions. We would have 

an interest in aligning with California’s emission standards, but they again do not have plans to 

extend their standards to high-altitude conditions. It may be appropriate for us to adopt Tier 3 

standards that apply equally at low- and high-altitude conditions, especially with the expected 

time frame for the Tier 3 standards. On the other hand, we would be open to considering the 

viability and effectiveness of allowing manufacturers to comply through an engineering analysis 

demonstrating that evaporative emission controls are no less effective at higher altitude.

Alan

_______________

1. Section 86.1810-09 is amended by revising paragraph (f)(1) to read as follows:

§ 86.1810-09 General standards; increase in emissions; unsafe condition; waivers.

* * * * *

(f) * * *
(1) All emission standards apply at low altitude conditions and at high altitude conditions, with 

the following exceptions:

(i) The supplemental exhaust emission standards as described in § 86.1811–04(f) apply only at 

low altitude conditions;

(ii) The cold temperature NMHC emission standards as described in § 86.1811–10(g) apply only 

at low altitude conditions;

(iii) The evaporative emission standards specified in § 86.1811-09(e) apply at low altitude 

conditions. The evaporative emission standards specified in § 86.1811-04(e) continue to 

apply at high altitude conditions for 2009 and later model year vehicles. 

* * * * *

2. Section 86.1811-09 is amended by revising paragraph (e) introductory text to read as 

follows:

§ 86.1811-09 Emission standards for light-duty vehicles, light-duty trucks and 

medium-duty passenger vehicles.

* * * * *

(e) Evaporative emission standards . Evaporative emissions from gasoline-fueled, natural 

gas-fueled, liquefied petroleum gas-fueled, ethanol-fueled and methanol-fueled vehicles must not 

exceed the standards in this paragraph (e) at low altitude conditions. The evaporative emission 

standards specified in § 86.1811-04(e)(1) continue to apply at high altitude conditions. The 

standards apply equally to certification and in-use vehicles.

* * * * *