ej#1 beam assemblies 1-hr fire rating

EJ#1

BEAM ASSEMBLIES

1-HR FIRE RATING

Engineering Judgement Report

Client Name: Bremik Construction

Client Address: 1026 SE Stark St, Portland, OR- 97214

Date: 1/19/2018


Code Unlimited LLC [2] www.codeul.com

Table of Contents 1 Project Overview ........................................................................................................................................ 3

2 Applicable Codes, Standards, and Guides ................................................................................................. 3

3 Discussion .................................................................................................................................................. 3

3.1 Approach ............................................................................................................................................. 3

4 Proposed design ........................................................................................................................................ 4

5 Assembly Analysis ...................................................................................................................................... 7

5.1 2”x6” Wood Block .............................................................................................................................. 10

6 Summary .................................................................................................................................................. 12

7 Conclusion ............................................................................................................................................... 13



1 PROJECT OVERVIEW

Bremik Construction is constructing a new apartment building at 2310 SE Hawthorne Blvd, Portland, OR. The

proposed 4 story mixed-use building includes 59 living units over retail space and 22 parking stalls at the

ground floor. The proposed building is 3-stories of Type VA construction over 1-story Type IA construction with

group R-2 (Residential), S-2 (Storage) and M (Mercantile) occupancies. The building is protected by an

automatic fire sprinkler and a fire alarm systems throughout.

The proposed W-beam assemblies are primary structural members supporting the rated roof in Type VA

construction building. The primary structural members are required to be 1-Hr fire resistance rated per 2014

Oregon Strutural Speciality Code (OSSC) table 601.

Code Unlimited has been asked to provide an analysis for the fire resistance rating of the beam assemblies

found in detail 14/A901 and 9/A960 to ensure they will meet the 1-Hr fire resistance rating per 2014 OSSC.

2 APPLICABLE CODES, STANDARDS, AND GUIDES

2014 Oregon Structural Specialty Code (OSSC) 2015 Technical Report NO. 10 – AWC (American Wood Council)

3 DISCUSSION

3.1 Approach

• The proposed beam assembly has been analyzed in accordance with 2014 OSSC §703.3 Alternative

Methods for Determining Fire Resistance.

• The protection for the proposed assembly has been reviewed for compliance with the requirements of 2014

OSSC §704 Fire Resistance Rating of Structural Members

• There are 2 proposed beam assemblies, each assembly will be analyzed in sections, starting from the bottom

and moving clockwise through left, top and right section of the assembly.



4 PROPOSED DESIGN

Assembly#1:

The proposed assembly is composed of W10x60 steel beam located at the 4th floor - roof assembly and

supporting the parapet (see Figure 1 below). The beam is considered as a primary structural member and will

be fire rated on all the exposed sides to meet 1-Hr fire resistance rating per 2014 OSSC table 601.



Figure 1: Proposed W10x60 beam assembly at Parapet



Assembly #2:

The proposed assembly is composed of a W10x60 steel beam located at the amenity deck of 4th story roof

assembly (see Figure 2 below). The beams are considered as a primary structural members and will be fire

rated on all exposed sides to meet 1-Hr fire resistance rating per 2014 OSSC table 601.

Figure 2: Proposed W10x60 beam assembly at Amenity Deck.



5 ASSEMBLY ANALYSIS

The summary of the fire analysis is detailed in the tables below. Table 1 provides analysis to the assembly #1

supporting the parapet. Table 2 provides analysis to the assembly #2 located at the amenity deck of the

building. The SFRM thickness applied to the exposed steel beam will be compared to the UL tested S721

beam assembly.

Figure 3: UL S721 Assembly



Table 1: Summary of Fire Resistance (Assembly #1)

Location on Beam

Protection Element

Bottom #1 • (2) layers of 5/8” Type X gypsum board • 80 minutes (40 minutes for each layer

of 5/8” Type X gyp board per table 722.6.2(1)

Total (60 min minimum) 80 min (Exceeds min protection)

Left Side Lower #2

• 7/16” thick SFRM applied on the exposed steel beam and steel bolt. (See summary section 6)

• 2x wood member bolted to the web flange

• 60 minutes (see Figure 3)

• 60 minutes (per char rate analysis-see section 5.1)

Total (60 min minimum) 60 min (Equivalent protection)

Left Side Upper #3

• 2”x6” sacrificial wood member • 60 minutes (per char rate analysis –

see section 5.1)


Top #4 • (2) 2”x6” wood block • 120 minutes (60 minutes for each

2”x6” wood member per char rate analysis see section 5.1)

Total (60 min minimum) 120 min (Exceeds minimum)

Right Side Lower #5






Fire-Resistance Rating

1-hour 1-hour (minimum)



Table 2: Summary of Fire Resistance (Assembly #2)

Location on Beam

Protection Element

Bottom #1 • (2) layers of 5/8” Type X gypsum board • 80 minutes (40 minutes for each layer

of 5/8” Type X gyp board per table 722.6.2(1)

Total (60 min minimum) 80 min (Exceeds min protection)

Left Side Lower #2






Left Side Upper #3


see section 5.1)


Top #4 • 2”x6” sacrificial wood member • 60 minutes (per char rate analysis –

see section 5.1)


Right Side Upper #5


see section 5.1)


Right Side Lower #6






Fire-Resistance Rating

1-hour 1-hour (minimum)



5.1 2”x6” Wood Block

The minimum wood thickness used as a protective material is 1.5” (actual thickness). The fire resistance of the

wood is permitted by OSSC Section 722.1 to be calculated using Chapter 16 of ANSI/AF&PA National Design

Specification for Wood Construction (NDS). The NDS specifies an effective char layer depth of 1.8” where 1-

hour of fire resistance is required based on equation 16.2-1 shown in Figure 4. Table 16.2.1A of the NDS is

reproduced below in Figure 5.

Figure 4: Equation 16.2-1 in the NDS

Figure 5: Table 16.2.1A of the NDS



Figure 6: NDS TR-10 Fig 3-8

NDS Calculation

Per Figure 5 and Figure 6, calculation for minimum wood cover (NDS TR-10 Fig 3-8).

Minimum Wood Cover Depth > achar /1.2. At 1 Hr = 1.8/1.2 = 1.5” minimum (60 Minutes).

As calculated above, 1.5” minimum actual wood thickness is necessary for 1-hour of fire resistance over steel

beam. The proposed 2”x6” thick wood will meet the minimum of 1-hour fire protection.



6 SUMMARY

We evaluated each face of the proposed protection for the W10x60 beam assembly to meet the equivalent

encapsulated 1-Hr fire resistance rating requirement per 2014 OSSC. The bottom of the steel beam is to be

protected with two layers of 5/8” Type X gypsum board. Each layer of 5/8” Type X gypsum board provides

minimum 40 minutes of protection to the assembly. From the component additive method, 2-layers of 5/8”

Type X gyp board provides 80 minutes of protection. The web flange of the proposed beams are protected with

blocking or (2x) sacrificial wood members on both sides and bolted through the beam with steel bolts. The

wood members provide a minimum of 60 minutes protection to the web flange per char rate analysis.

The edges of the steel flange and the exposed steel bolts are protected with SFRM (Spray Applied Fire

Resistive Material). The SFRM thickness is calculated based on the comparison to UL tested S721 design

assembly for W6x16 beam. The proposed beam W10x60 flange and steel bolts have greater W/D ratio (W/D -

1.22 & 1.73) (Weight to Heated Perimeter) compared to the tested W6x16 assembly (W/D 0.684). The tested

assembly requires application of 7/16” thick SFRM to meet 1-Hr fire rating. The application of 7/16” thick SFRM

to the exposed flanges and the steel bolts exceeds the minimum required fire resistance to the assembly.

The other sections of the proposed beam will be protected with minimum layer of 2”x6” sacrificial wood block.

The 2”x6” wood block provides 60 minutes of fire protection to the assembly per the char rate analysis detailed

in the section above. With this added protection, the proposed beam assemblies will meet the equivalent

minimum required 1-Hr fire resistance rating per 2014 OSSC.



7 CONCLUSION

We have evaluated the protection per 2014 OSSC section 703.3. All sides of the proposed beam assemblies

are protected equivalent to an encased structural member by minimum 2” nominal thick wood members, SFRM

coating or a combination of both. The material will remain in place and provide the required protection from fire

for all sides of the beam. The NDS calculation confirms that 1.5” will be the minimum cover for 1-Hr of fire

resistance, while the component additive method from OSSC confirms adequate fire resistance with (2) layers

of Type X gypsum board.

As shown above, the steel beam assembly is provided with a minimum fire protection of 1-Hr. By providing fire

resistance on all the sides for the length of the beam, the proposed beam assembly will have protection

equivalent to the required 1-Hr fire resistance rated encasement per 2014 OSSC section 704.3

Franklin Callfas

Principal/Fire Protection Engineer

Code Unlimited

ej#1 beam assemblies 1-hr fire rating

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