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EVERGREEN ENGINEERING
. Engineering and Construction Services E C `IY D
. ,'r 7431 NW Evergreen Pkwy., Suite 210, Hillsboro, OR 97124 -5831
: • • : . (503) 439 -8777 Fax (503) 439 -8767 www.evergreenengineering corn MAY 2 5 200 /
.
CITY OF f f A9D ti
May 23, 2007 BUILDING. DIVISION
To: Brian Blalock
City of Tigard
Building Department
13125 SW Hall Blvd
Tigard, OR 97223
503 -639 -4171
Project: Hemcon 3 Lyo and Facility Expansion (Permit BUP2007- 00191)
Subject: Request to construct stairway to equipment platform to OSHA not IBC
1. Requested Modification: I am requesting approval of the construction of the stairway for the
equipment platform according to the OSHA 1910.24 Fixed Industrial Stairs in place of the 2004
Oregon Structural Specialty Code requirements for stairway construction.
2. Explanation and Code Reference: The reason this should be allowed is that an equipment
platform according to section 505.5 Industrial Equipment Platforms of the 2004 Oregon
Structural Specialty Code is allowed to have "...stairs or ladders providing access to an
equipment platform...". This reference is made to egress requirements of the platform which
means that ladders are acceptable for a means of access, whereas, mezzanines don't have a
reference to ladders. As a ladder is acceptable then a stairway would be desirable from a
safety standpoint. If we are to construct a stairway constraints do not allow us to have
room for the OSSC requirements for rise and run, however, the OSHA requirements for
industrial stairways provides more leeway for steeper rise and run configurations.
3. Plan of Action: We would like to construct the stairway for access to the equipment platform
following the OSHA guidelines, because otherwise we will be forced to install a ladder which
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we believe has less egress capability and more safety issues.
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GENERAL BUILDING HEIGHTS AND AREAS
504.2 Automatic sprinkler system increase. Where a build- one -half of the area of the room in buildings and
ing is equipped throughout with an approved automatic sprin- structures equipped throughout with an approved
kler system in accordance with Section 903.3.1.1, the value automatic sprinkler system in accordance with Sec -
specified in Table 503 for maximum height is increased by 20 tion 903.3.1.1 and an approved emergency
feet (6096 mm) and the maximum number of stories is voice/alarm communication system in accordance
increased by one. These increases are permitted in addition to with Section 907.2.12.2.
the area increase in accordance with Sections 506.2 and 506.3. 5053 Egress. Each occupant of a mezzanine shall have access s
For Group R buildings equipped throughout with an approved to at least two independent means of egress where the common
automatic sprinkler system in accordance with Section path of egress travel exceeds the limitations of Section 1014.3.
903.3.1.2, the value specified in Table 503 for maximum height Where a stairway provides a means of exit access from a mez-
is increased by 20 feet (6096 mm) and the maximum number of zanine, the maximum travel distance includes the distance tray -
stories is increased by one, but shall not exceed 60 feet (18 288 eled on the stairway measured in the plane of the tread nosing.
mm) or four stories, respectively. Accessible means of egress shall be provided in accordance
Exceptions: with Section 1007.
1. Fire areas with an occupancy in Group I -2 of Type Exception: A single means of egress shall be permitted in
1.1B, III, IV or V construction. accordance with Section 1015.1.
2. Fire areas with an occupancy in Group H -1, H -2, H -3 505.4 Openness. A mezzanine shall be open and unobstructed
or H-5. to the room in which such mezzanine is located except for walls
3. Fire - resistance rating substitution in accordance with not more than 42 inches (1067 mm) high, columns and posts.
Table 601, Note e. Exceptions: •
504.3 Roof structures. Towers, spires, steeples and other roof 1. Mezzanines or portions thereof are not required to be
structures shall be constructed of materials consistent with the open to the room in which the mezzanines are located,
required type of construction of the building except where provided that the occupant load of the aggregate area
other construction is permitted by Section 1509.2.1. Such of the enclosed space does not exceed 10.
structures shall not be used for habitation or storage. The struc-
tures shall be unlimited in height if of noncombustible materi- 2. A mezzanine having two or more means of egress is
als and shall not extend more than 20 feet (6096 mm) above the not required to be open to the room in which the mez-
allowable height if of combustible materials (see Chapter 15 zanine is located if at least one of the means of egress
for additional requirements). provides direct access to an exit from the mezzanine
level.
3. Mezzanines or portions thereof are not required to be
SECTION 505 open to the room in which the mezzanines are located,
MEZZANINES provided that the aggregate floor area of the enclosed
505.1 General. A mezzanine or mezzanines in compliance space does not exceed 10 percent of the mezzanine
with Section 505 shall be considered a portion of the story area.
below. Such mezzanines shall not contribute to either the build- 4. In industrial facilities, mezzanines used for control
ing area or number of stories as regulated by Section 503.1. The equipment are permitted to be glazed on all sides.
area of the mezzanine shall be included in determining the fire
area defined in Section 702. The clear height above and below 5. In other than Groups H and I occupancies no more
the mezzanine floor construction shall not be less than 7 feet than two stories in height above grade plane and
(2134 mm) equipped throughout with an automatic sprinkler sys-
tem in accordance with Section 903.3.1.1, a mezza-
505.2 Area limitation. The aggregate area of a mezzanine or nine having two or more means of egress shall not be
mezzanines within a room shall not exceed one -third of the required to be open to the room in which the mezza-
floor area of that room or space in which they are located. The is located.
enclosed portion of a room shall not be included in a determina-
tion of the floor area of the room in which the mezzanine is 505.5 Equipment platforms. Equipment platforms in build- I located. In determining the allowable mezzanine area, the area ings shall not be considered as a portion of the floor below.
of the mezzanine shall not be included in the floor area of the Such equipment platforms shall not contribute to either the
room. building area or the number of stories as regulated by Section
503.1. The area of the equipment platform shall not be included I
Exceptions: in determining the fire area. Equipment platforms shall not be a
1. The aggregate area of mezzanines in buildings and part of any mezzanine_ and such platforms and the walkways,
structures of Type I or II construction for special -stars-and - ladders providing . accesi `to- an=equipme`nt-plaatform)
industrial occupancies in accordance with Section shall not serve as a part of the means of egress from the build-
.
I 503.1.1 shall not exceed two- thirds of the area of the ing•
room.
505.5.1 Area limitations. The aggregate area of all equip -
2. The aggregate area of mezzanines in buildings and ment platforms within a room shall not exceed two thirds of
structures of Type I or II construction shall not exceed the area of the room in which they are located. Where an
2006 INTERNATIONAL BUILDING CODE 77
JAN •Leia7
Oregon Administrative Rules FIXED INDUSTRIAL
Oregon Occupational Safety
and Health Division STAIRS
§1910.24 FIXED INDUSTRIAL STAIRS.
(a) Application of requirements. This section contains specifications for the safe
design and construction of fixed general industrial stairs. This classification includes
interior and exterior stairs around machinery, tanks, and other equipment, and stairs
leading to or from floors, platforms, or pits. This section does not apply to stairs used for
fire exit purposes, to construction operations to private residences, or to articulated
stairs, such as may be installed on floating roof tanks or on dock facilities, the angle of
which changes with the rise and fall of the base support.
(b) Where fixed stairs are required. Fixed stairs shall be provided for access from
one structure level to another where operations necessitate regular travel between
levels, and for access to operating platforms at any equipment which requires attention
routinely during operations. Fixed stairs shall also be provided where access to eleva-
tions is daily or at each shift for such purposes as gauging, inspection, regular main-
tenance, etc., where such work may expose employees to acids, caustics, gases, or
other harmful substances, or for which purposes the carrying of tools or equipment by
hand is normally required. (It is not the intent of this section to preclude the use of fixed
ladders for access to elevated tanks, towers, and similar structures, overhead traveling
cranes, etc., where the use of fixed ladders is common practice.) Spiral stairways shall
not be permitted except for special limited usage and secondary access situations
where it is not practical to provide a conventional stairway. Winding stairways may be
installed on tanks and similar round structures where the diameter of the structure is not
less than five (5) feet.
(c) Stair strength. Fixed stairways shall be designed and constructed to carry a load
of five times the normal live load anticipated but never of less strength than to carry
safely a moving concentrated load of 1,000 pounds.
(d) Stair width. Fixed stairways shall have a minimum width of 22 inches.
(e) Angle of stairway rise. Fixed stairs shall be installed at angles to the horizontal of
between 30° and 50 °. Any uniform combination of rise /tread dimensions may be used
that will result in a stairway at an angle to the horizontal within the permissible range.
Table D -1 gives rise /tread dimensions which will produce a stairway within the permis-
sible range, stating the angle to the horizontal produced by each combination. However,
the rise /tread combinations are not limited to those given in Table D -1. ,
TABLE D -1
Angle to Rise Tread run Angle to Rise Tread run
horizontal (in inches) (in Inches) horizontal (in inches) (In Inches) .
30 °35' .. 6 -1/2 11 41°44' 8 -1/4 9 -1/4
32 °08' 6 -3/4 10 -3/4 43 °22' 8- 1/2 ............... 9
33 °41' . ...... 7 . 10 -1/2 45 °00' .... .......... 8 -3/4 8 -3/4
35 °16' . .... 7 -1/4 10 -1/4 46 °38' 9 . 8 -1/2
36 °52' 7 -1/2 10 48 °16' 9 -1/4 .. ............ 8 -1/4
38 °29' .. 7 -3/4 9 -3/4 49 °54' 9 -1/2 8
40 °08' 8 9 -1/2
_ r
1910.24 D - 23 (a) - (e) Table D -1
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BUILDING DIVISION
T I G A R D TRANSMITTAL LETTER
TO: V‘., 4" a\ c\ c �_ DATE RECEIVED:
DEPT: BUILDING DIVISION
: ( . 2 ; FROM: S t Q �� ;�.; 0
COMPANY: c �-2,s L;��. �' WILDING i�iVisi4��:
PHONE: �p� J
(6.0-
RE: ���-� �w C�� � �� . 41 Y3� ��? �\S\
(Site Address (Permit/Case
C (DA
(Project name or subdivision name and lot number)
ATTACHED ARE THE FOLLOWING ITEMS:
I Copies: I Description: I Copies: I Description:
Additional set(s) of plans. Revisions:
Cross section(s) and details. Wall bracing and/or lateral analysis.
Floor /roof framing. Basement and retaining walls.
Beam calculations. Engineer's calcuktions.
k Other (explain):
REMARKS: ( J Jr1Y1)
FOR OFFICE USE ONLY
Routed to Permit Techn�ici Date: Initials:
Fees Due: ❑ Yes [ No Fee Description: Amount Due:
Special
Instructions:
Reprint Permit (per PE): ❑ Yes [ 1 o ❑ Done
Applicant Notified: Date: Initials:
I:\Buildmg\Forms \Transmittal Letter- Revisions .doc 4/4/07