In the Matter of the Petition of Todd Geske to Cease Enforcement of an Unadopted Rule Pursuant to Minn. Stat. § 14.381.

This opinion is nonprecedential except as provided by
Minn. R. Civ. App. P. 136.01, subd. 1(c).

STATE OF MINNESOTA
IN COURT OF APPEALS
A25-0214

In the Matter of the Petition of Todd Geske to Cease Enforcement
of an Unadopted Rule Pursuant to Minn. Stat. § 14.381.

Filed October 20, 2025
Reversed; rule declared invalid
Bond, Judge

Office of Administrative Hearings
File No. OAH-21-1902-39047

Mark R. Becker, Lucas T. Clayton, Fabyanske, Westra, Hart & Thomson, P.A.,
Minneapolis, Minnesota (for petitioner Todd Geske)

Keith Ellison, Attorney General, Kaitrin C. Vohs, Assistant Attorney General, St. Paul,
Minnesota (for respondent Minnesota Department of Labor and Industry)

Christopher W. Boline, Lauren C. Janochoski, Felhaber Larson, Minneapolis, Minnesota
(for amicus Builders Association of the Twin Cities d/b/a Housing First Minnesota)

Considered and decided by Ross, Presiding Judge; Bond, Judge; and Jesson, Judge.∗
NONPRECEDENTIAL OPINION
BOND, Judge
Petitioner Todd Geske, a municipal building official, challenges the decision of an
administrative-law judge (ALJ) under Minn. Stat. § 14.381 (2024). Geske argues that the
ALJ erred in determining that respondent Minnesota Department of Labor and Industry

∗ Retired judge of the Minnesota Court of Appeals, serving by appointment pursuant to
Minn. Const. art. VI, § 10.
2
(DLI) has not enforced an unpromulgated rule in interpreting and applying section 309.2.1
of the 2015 Minnesota Mechanical Code to require specific room-level airflow balancing
in single-family dwellings. We conclude that DLI is enforcing an unpromulgated rule. We
further conclude that, because section 309.2.1 is ambiguous and DLI does not argue that
its interpretation of section 309.2.1 is a long -standing one, DLI’s unpromulgated rule is
invalid. We therefore reverse.
FACTS
This case involves DLI’s interpretation of the Minnesota State Building Code,
Minn. Stat. §§ 326B.101-.194 (2024) (building code). DLI adopted the building code to
provide statewide standards that govern the “design, construction, . . . use and occupancy,
. . . and inspection of any building.” Minn. R. 1300.0040, subp. 1. The building code is
comprised of 21 different chapters, including the Minnesota Mechanical Code (mechanical
code),1 Minn. R. 1346.0050-.1500 (2015), and the Minnesota Residential Energy Code
(energy code), Minn. R. 1322.0010-.0500 (2015). Minn. R. 1300.0050 (2015).2
The dispute here primarily involves interpretation of section 309.2.1 of the
mechanical code and DLI’s application of that section’s airflow balancing requirements to

1 For its mechanical code, Minnesota has incorporated by reference the 2012 International
Mechanical Code. Minn. R. 1346.0050 (2015). The term “mechanical code” therefore
refers to the International Mechanical Code, subject to amendments to that code as set forth
in the administrative rules. See Minn. R. 1346.0050-.1500 (2015). This opinion primarily
cites to the amendments to the International Mechanical Code as found in the
administrative rules and otherwise cites the 2012 International Mechanical Code.

2 Although the record does not reflect the construction date of the home that is at issue in
this case, the parties agree that the 2015 mechanical code applies.
3
a heating, ventilation, and air conditioning (HVAC) system in a single-family dwelling.
As we explain in more detail below, section 309.2, entitled “Balancing,” provides that “[a]ll
mechanical ventilation and hydronic systems shall be capable of being balanced in
accordance with this section.” Minn. R. 1346.0309.2. Section 309.2.1 provides that
“[m]echanical ventilation systems shall provide airflow rates within +/- 10 percent of
design capacities and fan speed shall be adjusted to meet design airflow conditions.” Minn.
R. 1346.0309.2.1.
The building code is enforced through building officials who are responsible for
issuing, reviewing, and closing permits once the completed work is determined to be in
compliance with the building code. Geske was the building official in the City of Otsego.
Geske issued a mechanical permit for the installation of an HVAC system in a single-
family home in Otsego. In 2021, DLI informed Geske that the homeowner had filed a
complaint related to the HVAC system’s performance. The homeowner’s complaint
alleged that several of the upstairs bedrooms could not maintain an adequate temperature
and that the homeowner had to use space heaters in the rooms.
In May 2021, DLI issued a correction notice to address several issues with the
HVAC system that were discovered after an initial inspection. The correction notice did
not reference section 309 of the mechanical code or mechanical ventilation balancing. DLI
sent several email communications to Geske and the builder concerning the steps necessary
to bring the HVAC system into compliance with the building code.
On October 21, 2021, after additional work on the HVAC system was authorized to
proceed, DLI emailed the builder and requested that the builder submit mechanical
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ventilation balancing reports reflecting airflow rates within +/- 10 percent, as required by
section 309.2.1 of the mechanical code. On November 4, 2021, DLI issued a second
correction notice to the builder, which required airflow measurements to comply with
section 309.2.1. In multiple follow-up emails, DLI reiterated its position that section
309.2.1 required “mechanical ventilation systems (i.e. furnace blower) airflow rates within
+/- 10 percent of design capacities.”
In response to DLI’s correction notice, the builder contended that section 309.2.1 of
the mechanical code did not apply to residential buildings and that, by relying on section
309.2.1, DLI was enforcing an unpromulgated rule. The builder submitted an alternative
design relying on the less stringent Air Conditioning Contractors of America (ACCA)
Standard 5, which requires that airflow be within +/- 20 percent of design capacities.
DLI rejected the builder’s alternative plan to use the +/- 20 percent airflow
tolerances authorized by ACCA Standard 5. Instead, DLI stated that section 309.2.1 “does
not exempt residential buildings” and it again requested that the builder provide
recalculated airflow values based on the +/- 10 percent standard established in section
309.2.1. DLI rejected the builder’s contention that it was rulemaking or implementing a
new interpretation of the building code, maintaining that it was applying existing
regulations from the building code.
After additional testing of the HVAC system, Geske concluded that the builder’s
alternative design, which was based on the ACCA Standard 5 of airflow within +/- 20
percent of design capacities, complied with the intent of the building code. Geske therefore
closed the permit, determining that no further work on the HVAC system was required.
5
The homeowner appealed Geske’s decision to close the permit. DLI, through its
Construction Codes and Licensing Division (CCLD), convened the State Building Code
Appeals Board (board) to determine whether the HVAC system complied with the building
code. Before the board, the homeowner argued that Geske improperly approved the ACCA
Standard 5 for calculating airflow in the HVAC system rather that the +/-10 percent of
design capacity rate required by section 309.2.1 of the mechanical code. Geske argued that
section 309.2.1 applied to mechanical ventilation systems designed to provide fresh air
throughout a building, not to air distribution systems in a single -family dwelling. Geske
maintained that fresh air ventilation of residential buildings is governed by the energy code
and, therefore, the homeowner’s HVAC system was not required to meet the airflow
tolerance required by section 309.2.1 of the mechanical code. Instead, Geske argued that
the ACCA S tandard 5, which requires airflow balancing at +/-20 percent, was the
appropriate standard.
After hearing testimony from witnesses and reviewing documents submitted by both
parties, the board determined that the permit was “inappropriately closed and should be
reopened to address section 309.2.1 mechanical ventilation system balancing.” The board
further determined that “[b]alancing means airflow through the system and registers within
+/- 10 percent of the design values stated for each space based on ACCA Manuals D, J
and S.”
6
Geske petitioned the Minnesota Office of Administrative Hearings (OAH)3 under
Minn. Stat. § 14.381, seeking an order directing DLI to cease enforcement of an
unpromulgated rule relating to the application of 309.2.1 to single-family dwellings. Geske
again argued that section 309.2.1 applies to fresh air ventilation systems but not air
distribution systems, that mechanical ventilation in single-family dwellings is governed by
the energy code, which does not require room-airflow balancing at +/- 10 percent of design
capacities, and that the ACCA S tandard 5 was appropriate for residential air distribution
systems. DLI argued that its communications did not amount to unpromulgated
rulemaking because it was applying the building code on a case-by-case basis, and, even if
it was rulemaking, its interpretation applying room-level airflow balancing at +/- 10 percent
in single-family dwellings complied with the mechanical code’s plain meaning.
The ALJ dismissed Geske’s petition. The ALJ noted that section 309.2.1 does not
exempt single-family dwellings from its provisions and that the plain meaning of
“mechanical ventilation” includes air distribution as well as fresh air ventilation. Without
expressly deciding whether DLI was engaged in rulemaking or applying the building code
on a case-by-case basis, the ALJ determined that the board’s “application and
interpretation” of section 309.2.1 “accords with the plain language of the rules” and,
therefore, DLI was not enforcing an invalid unpromulgated rule.

3 The Office of Administrative Hearings was renamed Court of Administrative Hearings,
effective August 1, 2025. 2025 Minn. Laws ch. 39, art. 2, § 17, at 23 (amending Minn.
Stat. § 14.48, subd. 1 (2024)).
7
Geske appealed the ALJ’s decision by filing a petition for a declaratory judgment
pursuant to Minn. Stat. §§ 14.381, .44, .45 (2024). Geske asks this court to reverse the
ALJ’s decision and declare that DLI is enforcing an unpromulgated rule by applying its
interpretation of section 309.2.1 of the mechanical code to require room-level airflow
balancing in single-family dwellings.
DECISION
An administrative “rule” is “every agency statement of general applicability and
future effect, including amendments, suspensions, and repeals of rules, adopted to
implement or make specific the law enforced or administered by that agency or to govern
its organization or procedure.” Minn. Stat. § 14.02, subd. 4 (2024). An agency must
generally adopt administrative rules through specific notice and comment procedures as
outlined in the Minnesota Administrative Procedure Act (MAPA), Minn. Stat. §§ 14.001-
.69 (2024). Cable Commc’ns Bd. v. Nor-West Cable Commc’ns P’ship, 356 N.W.2d 658,
667 (Minn. 1984); In re Shakopee Mdewakanton Sioux Cmty., 988 N.W.2d 135, 141 (Minn.
App. 2023). Administrative rules that have gone through MAPA’s notice-and-comment
procedures are known as “promulgated rules,” while administrative rules that have not are
“unpromulgated rules.” Shakopee Mdewakanton Sioux Cmty., 998 N.W.2d at 141.
An individual may petition the OAH for an ALJ to “determin[e] that an agency is
enforcing or attempting to enforce a policy, guideline, bulletin, criterion, manual standard,
or similar pronouncement as though it were a duly adopted rule.” Minn. Stat. § 14.381,
subd. 1(a). The ALJ’s decision may then be appealed to this court through a petition for a
declaratory judgment under Minn. Stat. §§ 14.44-.45.
8
As a threshold matter, we must determine the standard of review that applies to our
review of an ALJ’s decision pursuant to Minn. Stat. § 14.381. Often, on review of an
agency decision, we employ the MAPA contested-case standard under Minn. Stat. § 14.69.
Minn. Ctr. for Env’t Advoc. v. Minn. Pollution Control Agency, 644 N.W.2d 457, 461
(Minn. 2002) (MCEA). 4 But here, because Geske filed a petition under Minn. Stat.
§ 14.381, subd. 1, there was no contested-case proceeding.
In MCEA, an environmental group brought a declaratory-judgment action
challenging a determination made by the Minnesota Pollution Control Agency. 644
N.W.2d at 459. The supreme court recognized that, under separation-of-powers principles,
“the legislature may not delegate to the courts duties which are essentially administrative
in character.” Id. at 464 (quotation omitted). Accordingly, in areas “uniquely involving
application of an agency’s expertise, technical training, and experience, the standard of
review set forth in MAPA is appropriate.” Id. The supreme court ultimately concluded
that, even though a contested-case proceeding had not been held, the MAPA standard was
appropriate. Id.
Following this reasoning, we conclude that the standard of review for an agency’ s
decision in a contested -case proceeding is applicable here. See Minn. Stat. § 14.69; see
also
In re Petition of Minn. Ass’n of Residential Servs. Homes (MARSH), No. A24-1562,
2025 WL1922283, at *3 (Minn. App. July 15, 2025) (determining that the MAPA

4 A contested case is a “proceeding before an agency in which the legal rights, duties, or
privileges of specific parties are required by law or constitutional right to be determined
after an agency hearing.” Minn. Stat. § 14.02, subd. 3.
9
contested-case standard was the appropriate standard of review of an ALJ’s decision
pursuant to Minn. Stat. § 14.381). 5 Under Minn. Stat. § 14.69, we may reverse or modify
an ALJ’s decision if the substantial rights of a party may have been prejudiced because the
decision was:
(a) in violation of constitutional provisions; or
(b) in excess of the statutory authority or jurisdiction of
the agency; or
(c) made upon unlawful procedure; or
(d) affected by other error of law; or
(e) unsupported by substantial evidence in view of the
entire record as submitted; or
(f) arbitrary or capricious.

We now turn to the parties’ arguments on appeal. Geske contends that DLI
announced an unpromulgated rule that section 309.2.1 of the mechanical code applies to
single-family dwellings and requires room-level airflow balancing (meaning airflow
balancing at individual registers) at +/- 10 percent of design capacities. Geske argues that
DLI’s unpromulgated rule is invalid because it is inconsistent with the plain language of
the building code. Geske further argues that, at a minimum, section 309.2.1 is ambiguous
and, because DLI does not claim that its interpretation of section 309.2.1 is a long-standing
one, DLI’s unpromulgated rule does not satisfy an exception to MAPA’s rulemaking
requirements.
DLI maintains that it is merely applying section 309.2.1 of the mechanical code to
a single HVAC system on a case-by-case basis. And DLI argues that, even if its

5 While nonprecedential, MARSH is persuasive authority on the issue of the appropriate
standard of review to apply review of an ALJ’s decision pursuant to Minn. Stat. § 14.381.
See Minn. R. Civ. App. P. 136.01, subd. 1(c).
10
interpretation and application of section 309.2.1 constitute d a rule, the ALJ correctly
determined that the rule was exempt from MAPA’s rulemaking requirements because its
interpretation of section 309.2.1 as requiring specific airflow balancing in single-family
dwellings comports with the mechanical code’s plain language. At oral argument, DLI
confirmed that it is not contending that its interpretation of section 309.2.1, if determined
to be a rule, was a long-standing one.
We therefore address whether DLI engaged in unpromulgated rulemaking and, if
so, whether the ALJ correctly determined that DLI’s unpromulgated rule was exempt from
the rulemaking requirements because it corresponds with the mechanical code’s plain
language.
I. DLI engaged in unpromulgated ruling.
An agency may develop policy either by rulemaking or by enforcing the law on a
case-by-case basis. Shakopee Mdewakanton Sioux Cmty., 988 N.W.2d at 143. An agency
formulates policy in a “rule” when it makes a “statement of general applicability and future
effect.” Minn. Stat. § 14.02, subd. 4. Interpretative rules, which are rules “that make
specific the law enforced or administered by the agency,” generally require the agency to
use MAPA’s notice-and-comment procedures. Cable Commc’ns Bd., 356 N.W.2d at 667
(quotation omitted).
An agency also formulates policy when it makes decisions on a case-by-case basis,
meaning the agency applies a law “to a specific party.” In re Hibbing Taconite Co., 431
N.W.2d 885, 894 (Minn. App. 1988). An agency does not engage in rulemaking when it
11
“enforces a law . . . by applying the law . . . to specific facts on a case-by-case basis.”
Minn. Stat. § 14.381, subd. 1(b).
Geske argues that DLI has adopted an unpromulgated rule interpreting section
309.2.1 as applying to single-family dwellings in Minnesota. DLI, on the other hand,
asserts that it was merely applying the mechanical code to a single HVAC system on a
case-by-case basis. The ALJ did not expressly decide whether DLI announced an
unpromulgated rule applying section 309.2.1 to single-family dwellings in Minnesota or
whether, conversely, DLI was not rulemaking because it was applying the law to specific
facts on a case-by-case basis. Instead, the ALJ dismissed Geske’s petition because it
determined that DLI’s interpretation and application of section 309.2.1 accorded with its
plain language and, therefore, DLI had not improperly promulgated a new rule.
Generally, we will not consider an issue not addressed in the proceeding below.
Thiele v. Stich, 425 N.W.2d 580, 582 (Minn. 1988). However, we may decide an issue not
determined in the final decision from which the appeal was taken when the “unaddressed
issue involves a question of law and the parties had an opportunity to brief the issue.” In
re Expulsion of A.D., 883 N.W.2d 251, 261 (Minn. 2016) (addressing issue related to a
ground for dismissal of student under the Minnesota Pupil Fair Dismissal Act, Minn. Stat.
§§ 121A.40-.575 (2014), despite issue not being decided by Commissioner of the
Minnesota Department of Education in the decision from which the student’s appeal was
taken). Here, the issue of whether DLI’s statements on section 309.2.1’s applicability were
a case-by-case application of the law or instead constituted a “statement of general
applicability and future effect” is a legal question. The issue was briefed by the parties in
12
the proceedings before the ALJ and has been fully briefed on appeal. We will therefore
address whether DLI was engaged in unpromulgated rulemaking.
In its October 2021 emails and the November 2021 correction notice, DLI directed
the builder to submit mechanical ventilation balancing reports reflecting airflow rates
within +/- 10 percent because, DLI asserted, that airflow rate was required by section
309.2.1 of the mechanical code. In multiple subsequent emails, DLI reiterated this position
on the applicability of section 309.2.1, stating that this section required “mechanical
ventilation systems (i.e. furnace blower) airflow rates within +/- 10 percent.” And, in
rejecting the builder’s alternative design that relied on the ACCA’s less stringent airflow
tolerance of +/- 20 percent of design capacities, DLI required the builder to recalculate the
HVAC system’s airflow tolerance based on the +/- 10 percent standard established in
section 309.2.1, stating that 309.2.1 “does not exempt residential buildings.” Finally, in its
determination that the permit needed to be reopened “to address section 309.2.1 mechanical
ventilation system balancing,” the board affirmed DLI’s interpretation of section 309.2.1
and stated that “[b]alancing means airflow through the system and registers within +/- 10
percent of the design values stated for each space based on ACCA Manuals D, J, and S.”
We conclude that DLI’s communications with the builder and the board’s balancing
definition constitute “statement of general applicability and future effect” regarding section
309.2.1’s applicability to single-family dwellings. Minn. Stat. § 14.02, subd. 4. Contrary
to DLI’s argument, the emails are not limited to the HVAC system in the homeowner’s
Otsego home. Rather, DLI’s communications articulate a general policy that section
309.2.1 of the mechanical code applies to single-family dwellings.
13
In Shakopee Mdewakanton Sioux Cmty., the Minnesota Gambling Control Board
(gambling board) sent an email to three vendors stating that “[g ]oing forward,” it would
not authorize certain electronic games based on the language of the governing statute. 988
N.W.2d at 140. The gambling board then reversed that position, emailing the same vendors
to state that it would “cautiously proceed” in considering those electronic games and
“continue to research” the matter going forward. Id. On appeal, we concluded that, while
the gambling board’s emails were sent to three specific vendors, the emails announced an
agency statement of general applicability such that it was an unpromulgated interpretative
rule. Id. at 145.
Like the gaming board’s emails in Shakopee Mdewakanton Sioux Cmty., DLI’s 2021
emails were sent to a specific builder and building official but they nonetheless
communicated a “statement of general applicability and future effect” because the emails
articulated a general policy that section 309.2.1 of the mechanical code requires room-level
airflow balancing in single-family dwellings. Minn. Stat. § 14.02, subd. 4. Accordingly,
we conclude that DLI issued an unpromulgated rule. See Cable Commc’ns Bd. , 356
N.W.2d at 667; Shakopee Mdewakanton Sioux Cmty., 998 N.W.2d at 144-45.
II. DLI’s unpromulgated rule is invalid.
We next consider whether the ALJ correctly determined that DLI’s unpromulgated
rule was exempt from the rulemaking requirements. An interpretative rule that has not
properly been promulgated may nonetheless be valid under one of two exceptions: (1) the
agency’s interpretation of a rule “corresponds with its plain meaning,” or (2) the rule is
ambiguous and the “agency interpretation is a longstanding one.” Cable Commc’ns Bd.,
14
356 N.W.2d at 667. “In either situation, the agency is not deemed to have promulgated a
new rule, and the agency’s interpretation is not invalid, although it does not have the force
and effect of law.” In re PERA Salary Determinations Affecting Retired & Active
Employees, 820 N.W.2d 563, 570 (Minn. App. 2012) ( quotations and citation omitted).
But, if an unpromulgated rule does not fall within one of those exceptions, it is invalid. In
re Contested Case of Good Neighbor Care Ctrs., Inc. v. Minn. Dep’t of Hum. Servs., 428
N.W.2d 397, 402 (Minn. App. 1988), rev. denied (Minn. Oct. 19, 1988).
Here, DLI does not argue that its interpretation of section 309.2.1 is a longstanding
one. Accordingly, only the plain-meaning exception is at issue. See Shakopee
Mdewakanton Sioux Cmty., 988 N.W.2d at 146 (“When an agency’s interpretation accords
with a statute’s plain language, the statute authorizes the agency’s interpretation and,
therefore, the agency did not promulgate a new rule subject to MAPA’s rulemaking
requirements.”). Interpretation of a statute o r administrative rule is a legal question that
appellate courts review de novo. J.D. Donovan, Inc. v. Minn. Dep’t of Transp., 878 N.W.2d
1, 5 (Minn. 2016).
To determine whether an agency’ s unpromulgated rule applied the rule’s plain
language, we do not analyze words in isolation but consider the meaning of the rule “in
accordance with the apparent purpose of the regulation as a whole.” In re Cities of
Annandale & Maple Lake NPDES/SDS Permit Issuance, 731 N.W.2d 502, 517 (Minn.
2007) (Annandale); see also Minn. Transitions Charter Sch. v. Comm ’r of Minn. Dep’t of
Educ., 844 N.W.2d 223, 227 (Minn. App. 2014), rev. denied (Minn. May 28, 2014). We
first determine “whether the statute or regulation is clear or ambiguous on its face.” In re
15
Minn. Living Assistance, Inc., 934 N.W.2d 300, 306 (Minn. 2019) (quotation omitted). In
determining whether a statute is ambiguous, we construe “the statute’s words and phrases
according to their plain and ordinary meaning.” In re Fin. Responsibility for Out-of-Home
Placement Costs for S.M., 812 N.W.2d 826, 829 (Minn. 2012). “A statute should be
interpreted, whenever possible, to give effect to all of its provisions; no word, phrase, or
sentence should be deemed superfluous, void, or insignificant.” Am. Fam. Ins. Grp. v.
Schroedl, 616 N.W.2d 273, 277 (Minn. 2000) (quotation omitted). A statute or rule is
ambiguous “if its language is subject to more than one reasonable interpretation.”
Christianson v. Henke, 831 N.W.2d 532, 537 (Minn. 2013). “Multiple parts of a statute
may be read together so as to ascertain whether the statute is ambiguous.” Id.
The parties’ dispute focuses on the meaning of section 309.2.1 of the mechanical
code. Section 309 of the mechanical code is entitled “Temperature Control.” Minn. R.
1346.0309. Section 309.2, entitled “Balancing,” provides that “[a]ll mechanical ventilation
and hydronic systems shall be capable of being balanced in accordance with this section.”
Minn. R. 1346.0309.2. Section 309.2.1, entitled “Mechanical ventilation system
balancing,” provides that “[m]echanical ventilation systems shall provide airflo w rates
within +/- 10 percent of design capacities and fan speed shall be adjusted to meet design
airflow conditions.” Minn. R. 1346.0309.2.1. Section 309.2.1 contains an exception that
states that speed adjustment is not required for fan motors rated at one horsepower or less.
Id.
We conclude that, considering the building code as a whole, section 309.2.1 is
susceptible to two reasonable interpretations regarding whether it requires room-level
16
airflow balancing, meaning balancing at each supply register and return, in single-family
dwellings within +/-10 percent of design capacities. Section 309.2.1 is, therefore,
ambiguous.
One reasonable interpretation, advanced by DLI and adopted by the ALJ, is that
residential buildings must comply with section 309.2.1 by balancing airflow through the
system and the registers within +/- 10 percent of the design as outlined by national
standards found in ACCA Manuals D, J, and S. As DLI argues, section 309 does not
contain an exception for residential buildings or single-family dwellings. And the
mechanical code generally regulates the installation of “mechanical systems that are
permanently installed and utilized to provide control of environmental conditions and
related process within buildings.” Minn. R. 1346.0101. “Mechanical system” is defined
as a “system . . . composed of components, devices, appliances, and equipment.” 2012
Int’l Mechanical Code § 202. A “building” is defined as “[a]ny structure occupied or
intended for supporting or sheltering any occupancy.” Id. Because, as DLI argues, an
HVAC system is a permanently installed mechanical system that provides control of
environmental conditions and a single-family dwelling is a building intended to be
occupied, it is reasonable to interpret section 309.2.1 as applying to HVAC systems in
single-family dwellings.
DLI further argues that the board’s definition of balancing “through the systems and
registers” in accordance with “ACCA Manuals D, J, and S” reflects existing building code
regulations. Because the mechanical code defines a “mechanical system” as one containing
“components,” the individual registers connected to the HVAC system are components
17
comprising the mechanical system being balanced. 2012 Int’l Mechanical Code § 202.
The energy code, which as we have explained is part of the building code, defines
“mechanical ventilation” as the “mechanical process of supplying conditioned or
unconditioned air to, or removing it from, any space,” which reasonably supports DLI’s
interpretation that, because mechanical ventilation is defined per space, balancing of such
ventilation must occur at each space. Minn. R. 1322.0202, subp. 1, R202 (emphasis
added).
Finally, DLI’s reasonable interpretation is supported by provisions of the e nergy
code requiring that HVAC systems be sized according to “ACCA Manual S” and based
upon the building’s heating and cooling load calculations as established by “ACCA Manual
J.” Minn. R. 1322.0403, subp. 2, R403.5.17. In addition, the mechanical code requires
that ducts installed in a single dwelling unit “shall be sized in accordance with ACCA
Manual D.” 2012 Int’l Mechanical Code § 603.2. Read together, these provisions support
the reasonable interpretation that an HVAC system must be balanced at each space, or
through the registers, in accordance with the standards outlined in ACCA Manuals D, J,
and S. Therefore, interpreting section 309.2.1’s words according to their “plain and
ordinary meaning,” and giving effect to all the building code’s provisions, DLI’s
interpretation of section 309.2.1 as requiring room-level airflow balancing in single-family
dwellings within +/- 10% is reasonable. See Christianson, 831 N.W.2d at 538; Shakopee
Mdewakanton Sioux Cmty., 988 N.W.2d at 146.
But Geske’s interpretation of section 309.2.1 is also reasonable. Geske asserts that
applying 309.2.1 to require balancing of airflow within +/- 10 percent of design capacities
18
at individual registers in single-family dwellings is inconsistent with multiple additional
provisions of the building code. See Annandale, 731 N.W.2d at 516, 518 (holding that
“statutory language, plain or not, depends on context” (quotation omitted)). Geske points
out that section 309.2.1 refers to “mechanical ventilation” and chapter 4 of the mechanical
code is entitled “Ventilation.” Thus, Geske argues, we should look to chapter 4’s
ventilation provisions to determine the meaning and applicability of section 309.2.1’s
“mechanical ventilation system balancing” provision.
Chapter 4 of the mechanical code “govern[s] the ventilation of spaces within a
building intended to be occupied” except for “residential buildings complying with the
ventilation requirements in [the energy code].” Minn. R. 1346.0401, subp. 1. The energy
code defines “mechanical ventilation” as the “mechanical process of supplying conditioned
or unconditioned air to, or removing it from, any space.” Minn. R. 1322.0202. Thus,
according to Geske’s interpretation, mechanical ventilation in residential buildings is
governed by the energy code, not by section 309.2.1 of the mechanical code.
Indeed, section 309.2.3 provides that “[s]ystems balancing reports. . . shall specify
that the minimum amount of outdoor air required in [International Mechanical Code]
[c]hapter 4, as amended, is provided to the ventilation system.” Minn. R. 1346.0309.2.3.
Section 309.2.3’s reference to “the ventilation system,” read in context with chapter 4’s
provision that the mechanical code’s ventilation requirements do not apply to residential
buildings that comply with the energy code , supports a reasonable interpretation that
ventilation of single-family dwellings is governed by the energy code, not section 309.2.1’s
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airflow balancing requirements. See Christianson, 831 N.W.2d at 538 (stating that, when
interpreting a rule, no word is “insignificant” or “superfluous” (quotation omitted)).
Further, the mechanical code does not provide a definition of “balancing” or
“mechanical ventilation balancing.” Section 201.3 of the mechanical code provides that
“[w]here terms are not defined in this code and are defined in the [Minnesota building
code] . . . such terms shall have meanings ascribed to them as in those codes.” 2012 Int’l
Mechanical Code § 201.3. The energy code defines a “balanced system” as “[a] ventilation
system in which the air intake is within ten percent of the exhaust output.” Minn. R.
1322.0202, subp. 1. These provisions of the building code support Geske’s reasonable
interpretation that, even if section 309.2.1 does apply to residential buildings, an HVAC’s
system balancing occurs only at the point of exhaust, not “through the system and
registers.” See Annandale, 731 N.W.2d at 516 (stating that words in a rule are to be
“viewed in their setting, not isolated from their context”).
In sum, it is reasonable to interpret section 309.2.1’s airflow balancing requirements
to not apply to single-family dwellings complying with the ventilation requirements of the
energy code. And, even if section 309.2.1 did apply to single-family dwellings, it is
reasonable to interpret the energy code as requiring system-level balancing, rather than
room-level balancing, in single-family dwellings. See Christianson, 831 N.W.2d at 538 ;
Shakopee Mdewakanton Sioux Cmty., 998 N.W.2d at 146.
We conclude that, when considered in the context of the building code as a whole,
there is more than one reasonable interpretation regarding whether section 309.2.1 requires
specific room-level airflow balancing within +/- 10 percent in single-family dwellings.
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Because section 309.2.1 is subject to more than one reasonable interpretation, it is
ambiguous. See Christianson, 831 N.W.2d at 537; Shakopee Mdewakanton Sioux Cmty.,
998 N.W.2d at 146. The ALJ therefore committed a legal error in concluding that DLI’s
interpretation of section 309.2.1 corresponds with the rule’s plain meaning. Because DLI’s
rule does not fit within MAPA’s exceptions, DLI has issued an invalid rule. See PERA,
820 N.W.2d at 573 (quotation omitted). Accordingly, we reverse and declare DLI’s
unpromulgated rule invalid.
Reversed; rule declared invalid.