PERMANENT RULES
Date of Adoption: November 17, 2000.
Purpose: To make changes to the Washington state amendments to the 1997 Uniform Mechanical Code, chapter 51-42 WAC.
Citation of Existing Rules Affected by this Order: Amending chapter 51-42 WAC, Sections 405, 1103, 1105, 1109, 1110, 1111, 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119, 1120, 1121, 1122, 1123, 1124, 1126, 1301.
Statutory Authority for Adoption: RCW 19.27.031, 19.27.074.
Adopted under notice filed as WSR 00-16-130 on August 2, 2000.
Changes Other than Editing from Proposed to Adopted Version: The proposed amendments to the following sections were not adopted: 1101.
Number of Sections Adopted in Order to Comply with Federal Statute: New 0, Amended 0, Repealed 0; Federal Rules or Standards: New 0, Amended 0, Repealed 0; or Recently Enacted State Statutes: New 0, Amended 0, Repealed 0.
Number of Sections Adopted at Request of a Nongovernmental Entity: New 18, Amended 3, Repealed 0.
Number of Sections Adopted on the Agency's Own Initiative: New 0, Amended 0, Repealed 0.
Number of Sections Adopted in Order to Clarify, Streamline, or Reform Agency Procedures: New 0, Amended 0, Repealed 0.
Number of Sections Adopted Using Negotiated Rule Making: New 0, Amended 0, Repealed 0; Pilot Rule Making: New 0, Amended 0, Repealed 0; or Other Alternative Rule Making: New 18, Amended 3, Repealed 0. Effective Date of Rule: July 1, 2001.
January 3, 2001
Tim Nogler
for Jim Lewis
Council Vice Chair
OTS-4187.3
NEW SECTION
WAC 51-42-0405
Section 405 -- Direct gas-fired make-up air
systems.
405.1 General. Direct gas-fired make-up air heaters shall not
be installed for comfort heating in other than Group F, S, or U
Occupancies.
| EXCEPTION: | Direct gas-fired make-up air heaters may be installed in accordance with Section 909. |
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1103.1 General. For the purposes of applying Tables 1104.1,
1104.2(1), and 1104.2(2), refrigeration systems shall be
classified as high-probability or low-probability system based on
the potential hazard resulting from a leakage of refrigerant into
an occupancy-classified area other than the machinery room.
1103.2 High-probability systems. Direct systems and indirect
open-spray systems shall be classified as high-probability
systems.
EXCEPTION:
An indirect open-spray system shall not be required to be classified as a high-probability system if the pressure
of the secondary coolant is at all times (operating and standby) greater than the pressure of the refrigerant.
1103.3 Low-probability((V)) systems. Double-indirect open-spray
systems, indirect closed systems and indirect-vented closed
systems shall be classified as low-probability systems, provided
that all refrigerant-containing piping and fittings are isolated
when the quantities in Table 1104.1 are exceeded.
[Statutory Authority: RCW 19.27.031 and 19.27.074. 98-02-056, 51-42-1103, filed 1/6/98, effective 7/1/98.]
1105.1 General. Where required by Table 1104.2(1), a machinery
room shall be provided to enclose refrigeration systems located
indoors. Access to the machinery room shall be restricted to
authorized personnel. For rooms where occupational exposure
could occur, see WAC 296-62-07515 and 296-62-3112.
1105.2 Dimensions. A machinery room shall be dimensioned so as
to provide clearances required by Chapter 3. There shall be
clear head room of not less than 7 feet 3 inches (2210 mm) below
equipment located over passageways.
1105.3 Doors. Each machinery room shall have self-closing,
weather-stripped doors opening in the direction of egress travel.
Doors and door openings shall comply with the requirements of the
Building Code.
1105.4 Openings. Openings to other parts of the building that
permit passage of escaping refrigerant to other parts of the
building are prohibited. Ducts and air handlers in the machinery
room that operate at a lower pressure than the room shall be
sealed to prevent any refrigerant leakage from entering the
airstream.
1105.5 Refrigerant vapor detector. Machinery rooms shall
contain a refrigerant vapor detector with an audible and visual
alarm. The detector, or a sampling tube that draws air to the
detector, shall be located in an area where refrigerant vapor
from a leak will concentrate. The alarm shall be actuated at a
value not greater than the corresponding TLV-TWA values shown in
Table 1104.1. Detectors and alarms shall be placed in approved
locations. Detection and alarm systems shall be powered and
supervised, monitored and annunciated, and installed and
maintained as required by Section 6313 of the Fire Code.EXCEPTIONS:
1. Egress doors serving the machinery room.
2. Access doors and panels in air ducts and air-handling units, provided that such openings are gasketed and
tight fitting.
EXCEPTION:
Detectors are not required for ammonia systems complying with Section 1106.8.
1105.6 Tests. Periodic tests of the detector, alarm and
mechanical ventilating system shall be performed in accordance
with manufacturer's specifications and as required by the code
official.
1105.7 Fuel-burning equipment. Open flames that use combustion
air from the machinery room shall not be installed in a machinery
room.
1105.8 Sign. A sign shall be posted on the machinery room door
prohibiting access of unauthorized personnel.EXCEPTIONS:
1. Matches, lighters, halide leak detectors and similar devices.
2. Where the refrigerant is carbon dioxide or water.
3. Fuel-burning equipment shall not be prohibited in the same machinery room with refrigerant-containing
equipment where combustion air is ducted from outside the machinery room and sealed in such a manner as to
prevent any refrigerant leakage from entering the combustion chamber, or where a refrigerant vapor detector is
employed to automatically shut off the combustion process in the event of refrigerant leakage.
1105.9 Ventilation. Machinery rooms shall be mechanically
ventilated to the outdoors. Mechanical ventilation shall be
capable of exhausting the minimum quantity of air both at the
normal operating and emergency conditions. Multiple fans or
multispeed fans shall be allowed in order to produce the
emergency ventilation rate and to obtain a reduced airflow for
normal ventilation. Fans providing refrigeration machinery room
temperature control or automatic response to refrigerant vapor
are allowed to be automatically controlled to provide
intermittent ventilation as conditions require.
EXCEPTION:
Where a refrigerating system is located outdoors more than 20 feet (6096 mm) from any building opening and
is enclosed by a penthouse, lean-to or other open structure, natural or mechanical ventilation shall be provided. Location of the openings shall be based on the relative density of the refrigerant to air. The free-aperture cross
section for the ventilation of the machinery room shall be not less than:
| Q = 0.07 x √G)) | |||
| F = √G | |||
| For SI: | F = 0.138 √G | ||
where:
F = The free opening area in square feet (m2).
G = The mass of refrigerant in pounds (kg) in the largest
system, any part of which is located in the machinery room.
1105.9.1 Discharge location. The discharge of the air shall be
to the outdoors in accordance with Chapter 5. Exhaust from
mechanical ventilation systems shall be discharged not less than
20 feet (6096 mm) from a property line or openings into
buildings.
1105.9.2 Supply air. Provisions shall be made for supply air to
replace that being exhausted. Openings for supply air shall be
located to avoid intake of exhaust air. Air supply and exhaust
ducts to the machinery room shall serve no other area, shall be
constructed in accordance with Chapter 5 and shall be covered
with corrosion-resistant screen of not less than 1/4 inch (6.4
mm) mesh. The supply air shall be taken from directly outside
the building. Intakes shall be fitted with backdraft dampers or
similar approved flow control means to prevent reverse flow.
1105.9.3 Quantity--normal ventilation. During occupied
conditions the mechanical ventilation system shall exhaust the
larger of the following:
1. Not less than 0.5 cfm per square foot (0.0025 m3/s m2) of
machinery room area or 20 cfm (0.009 m3/s) per person; or
2. A volume required to maintain a maximum temperature rise of
18F (-7.8C) based on all of the heat-producing machinery
in the room.
1105.9.4 Quantity--emergency conditions. Upon actuation of the
refrigerant detector required in Section 1105.5, the mechanical
ventilation system shall exhaust air from the machinery room in
the following quantity:
| F = 0.138 √G)) | |||
| Q = 100 x √G | ||
| For SI: | Q = 0.07 x √G |
where:
Q = The airflow in cubic feet per minute (m3/s).
G = The design mass of refrigerant in pounds (kg) in the largest
system, any part of which is located in the machinery room.
1105.10 Termination of relief devices. In the equipment room,
pressure relief devices, fusible plugs and purge systems shall
terminate outside of the structure at a location not less than 15
feet (4572 mm) above the adjoining grade level and not less than
20 feet (6096 mm) from any window, ventilation opening or exit.
[Statutory Authority: RCW 19.27.031 and 19.27.074. 98-02-056, 51-42-1105, filed 1/6/98, effective 7/1/98.]
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Table 11-A - Refrigerant groups, properties and allowable
quantities. This table is not adopted.
Table 11-B - Permissible refrigeration systems and
refrigerants. This table is not adopted.
Table 11-C - Value of f (f) for equation 11-7. This table
is not adopted.
Table 11-D - Field leak test pressures in psig. This table
is not adopted.
Table 11-E - Condensate waste size. This table is not
adopted.
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1301.2 Other authorities. In addition to the Uniform Mechanical
Code, provisions of chapter 480-93 WAC regarding gas pipeline
safety may also apply to single meter installations serving more
than one building. The provisions of chapter 480-93 WAC are
enforced by the Washington Utilities and Transportation
Commission.
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