Steel Beam SFRM Protection - Portland, Oregon

Steel Beam SFRM Protection

Engineering Judgement Report-EJ#1

Client Name: Hacker

Client Address: 1615 SE 3rd Ave, Portland, OR 97214

Date: 7/6/2018

Engineering Judgement Report

Code Unlimited LLC [2] www.codeul.com

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

2 Applicable Codes, Standards, and Guides ................................................................................................. 4

3 Discussion .................................................................................................................................................. 4

3.1 Approach ............................................................................................................................................. 4

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

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

6 Summary .................................................................................................................................................. 11

7 Conclusion ............................................................................................................................................... 12



1 PROJECT OVERVIEW

Hacker is renovating Neuberger Hall located in Portland, Oregon on the Portland State University Campus.

The building was constructed in the 1960s under the 1958 and 1967 building codes and is divided into the East

and West wings. Neuberger Hall is a 5 story, Type IIA building with B, A-3, and S-1 occupancies. The building

is protected by an automatic sprinkler and fire alarm systems throughout. Some of the structural steel beams in

the building have been reconfigured at the intersecting joints and the original fire proofing has been removed

(See Figure 1 below).

Code Unlimited has been asked to perform an analysis of the exposed steel beams and provide an

engineering judgment to address the required continuity of fire protection for the steel beams with new spray

fire resistive material (SFRM) adjacent to the original asbestos based fire protection.



2 APPLICABLE CODES, STANDARDS, AND GUIDES

2014 Oregon Structural Specialty Code

3 DISCUSSION

3.1 Approach

• The protection requirements of the beam assemblies have been analyzed in accordance with 2014 OSSC

§703.3 Alternative Methods for Determining Fire Resistance.

• Portions of the tested assembly are modified to suit the unique design conditions. The modification is

analyzed for equivalency using published ASTM E119 fire test data and acceptable fire analysis.

• Appendix A contains the construction drawings that reference the required fire resistance rating for the steel

beams and their location in the building.

4 PROPOSED DESIGN

The subject W beams are connected to a primary structural columns and can be found at multiple locations in

the building (see Figure 1). These restrained members are reviewed as part of the primary structure. Per 2014

OSSC Table 601, primary structural members for this building are required to be minimum 1 hr. fire rated. It is

assumed that the beam will be exposed to fire and the assembly will require continuous protection from the

exposed three sides.

A 12 inch wide metal lath sheet will be attached at the intersection between the existing asbestos coating and

the bare steel beam (see Figure 2). The metal lath is 3.4 lb/yd2 galvanized steel and will be attached by self-

tapping screws and washers to the bare steel. The metal lath will overlap the exposed steel and asbestos

coating by 6 inches. Prior to application of the CAFCO 300SB SFRM, the asbestos fire proofing will be covered

with AsbestosSafe encasement for HSE concerns. The Class A, AsbestosSafe coating will be applied per the

manufacturer’s recommendations.



Figure 1: Typical existing beam assembly with plaster protection on the column and an asbestos fire

protection coating on the beams



Figure 2: Side view and Section view of proposed beam assembly



5 ASSEMBLY ANALYSIS

Exposed primary structural members are required to be protected to an hourly rating per Table 601. The

existing beam protection requirements are 1-hr rating for W12x14 and 2 hours for W12x22 (See Appendix A for

locations-Structural Fire Resistance Plan).

To meet the minimum fire resistance requirements, the proposed W beam assembly is compared to the UL

tested N759 beam assembly (shown in Figure 3 below). The comparison and analysis are listed in the Table 1

below.



Figure 3: Listed UL Beam Assembly N759



Figure 4: Isolatek W/D Thickness Manual comparison table for UL N759



Element UL Assembly Design No. N759 Proposed Assembly

1. Structural Material

Steel Beam; W8x28 min size

(W/D = 0.81 - Beam)

(see Figure 2)

Steel Beam; W12x14

(W/D =.4 - Beam),

(See Fig 3)

(Equivalent)

2. Concrete type

Normal weight or lightweight concrete, 2-1/2 in. min thickness over the steel floor and form unit crests or min 3 in. thick slab with a compressive strength of 3500 psi and min dry unit weight of 110 pcf.

Existing lightweight, 3” Minimum thickness

(Equivalent)

3. Shear Connector (optional)

Studs, ¾ in. diam headed type. Welded to the top flange of beam through the steel floor units.

Attachment not included in review.

4. Welded.Wire Fabric (optional)

6x6-10/10 SWG N/A

5. Steel Floor and Form Units

1-1/2, 2, or 3” deep fluted, cellular or corrugated units welded to beam.

¾” thick corrugated steel deck unit welded to beam

(Equivalent)

6. Lath Hangers (optional)

No. 6 SWG steel wire, spaced 27 in. OC max

N/A

7. Metal Lath (Optional)

3.4 lb/sq. yd galv or painted expanded steel. Attached by gunned or stud welded pins at max 24 in. OC with 1-1/2-3 inch overlaps

3.4 lb/sq. yd galv steel lath. Attached by self-tapping Tek screws (size min #12) with washers to top and bottom flanges only (Not web).

8. Spray-Applied Fire Resistive Materials

Prepared by mixing with water. Spray-Applied in one or more coats to beam surfaces to a min final thickness as shown in the tables below. Beam surfaces must be clean and free of dirt, loose scale, and oil. Crest areas of deck above the beams shall be filled with spray-Applied Fire Resistive Materials. Min average and min individual density of 15 pcf, and 14 pcf respectively for types 300. 5/16” min thickness.

CAFCO 300 SB Spray-Applied in one or more coats to beam surfaces to a min final thickness as shown in the tables below. Beam surfaces must be clean and free of dirt, loose scale, and oil. Crest areas of deck above the beams shall be filled with spray-Applied Fire Resistive Materials. Min average and min individual density of 15 pcf, and 14 pcf respectively for types 300. Spray-Applied Fire Resistive coating, applied 1/2” thick on the steel beam per attached table (Fig. 4).

Fire-Resistance Rating

1-Hour 1-Hour (minimum)

Table 1: Comparison between Tested and Proposed beam assembly



6 SUMMARY

While evaluating fire resistance requirement of members, different sized beam and columns are compared

against each other through a factor referred to as the W/D Ratio. The weight per unit length of a member is

divided by the length of exposed heated perimeter area to determine the inherent fire resistance of a member.

Lower W/D ratios correspond with thinner steel members that will be subject to premature failure when heated.

We compared the W beam assembly with a fully loaded restrained beam assembly of UL N759 (heated on 3

sides). From the Isolatek comparison table above, we can see that for our proposed beams (W12x14 and

W12x22) with a fire resistance rating of 1 and 2 hours will require a SFRM thickness listed in Table 2. The

formed heavy gauge metal lath is used to bridge the gap between the existing asbestos material and the newly

applied SFRM. The overlapping 6” of required SFRM on the formed lath will ensure adequate protection

continuity of the fire proofing. The attachment locations for the metal lath have been coordinated with the

project structural engineer.

Minimum application thickness is listed in Table 2

Beam Size Fire Resistance Rating (Hr) Required SFRM Thickness

W12x14 1 ½”

W12x22 2 11/16”

Table 2: SFRM Required Application



7 CONCLUSION

I have reviewed the proposed member protection against an applicable UL test. The evaluation from N759

(beam) of CAFCO 300 SB SFRM coating for fire proofing the existing W Beam will comply with the required 1

or 2-hr fire resistance requirements if applied to bare steel or metal lath as directed above to the required

thickness.

As detailed in this EJ, the proposed design for the W beam will maintain fire rating continuity when entirely

covered on 3 sides and overlapping the existing protection. The protection will meet or exceed the required

ratings as compared and detailed in this letter with UL fire assembly N759.

Franklin Callfas

Principal/Fire Protection Engineer

Code Unlimited

Steel Beam SFRM Protection - Portland, Oregon

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