Appeal 11405

Table 601

One hour rating of Primary Structural Frame for Type III-a Construction

The existing building was built in the 1890’s and has brick bearing walls around its entire perimeter except from the basement to the second floor at the north and east sides. The interior heavy timber structural floor frame is supported by cast iron pipe columns varying in size from 9” diameter (basement) to 5” diameter (fifth floor), with wall thickness of 1”. The proposed design is to coat all interior pipe columns from basement through roof with intumescent paint to achieve a one hour rating. The building is fully sprinklered.

A tested assembly for cast iron columns protected with intumescent paint does not exist, and the cost of such a test is extravagantly expensive to perform on a building material that was no longer commonly used structurally after the 1900s. In lieu of formal physical testing of the assembly the appellant has done considerable research to prove that the proposed intumescent coating thicknesses and products selected will perform to their require fire resistance ratings. Working with a fire protection engineer and a representative from Carboline, we have established a paint thickness that will protect the column from reaching its yield point of failure beyond 1 hour. The process for creating this thickness is described in supporting documents as listed below including a letter from a fire protection engineer (3.1). Please reference Detail 3 (3.2) for the plan section of the described column.

3.1 Letter from David Gessert, fire protection engineer
3.2 Detail 3 Interior pipe column plan section
3.3 Carboline Product Data: A/D Firefilm III
3.4 Carboline Letter: A/D Firefilm III

The use of intumescent paint allows a cost effective approach to fire proofing the building and allows the original structure of the building to be exposed and expressed.
With the proposed measures listed above, we believe that the fire safety of the columns is not compromised by the alternate method proposed and equivalent performing life safety and fire protection measures are provided.

Code Section: Table 601, 704.10

Section 704.10 requires load bearing structural members located within the exterior walls to be provided with the highest fire-resistive rating as determined in accordance with table 601 for exterior bearing walls.

Table 601 requirement for exterior bearing walls for type III-A is a 2 hour fire-resistive rating.

The existing building was built in the 1890’s and has brick bearing walls around its entire perimeter except from the basement to the second floor at the north and east sides. The exterior masonry wall is supported by large I-section cast iron columns (referred to a “double E columns”) following the perimeter of the building. The proposed design is to coat all of these columns from the first floor to the second at the beginning of the masonry wall with intumescent paint to achieve a two hour rating. The building is fully sprinklered.

A tested assembly for cast iron columns protected with intumescent paint does not exist, and the cost of such a test is extravagantly expensive to perform on a building material that was no longer commonly used structurally after the 1900s. In lieu of formal physical testing of the assembly the appellant has done considerable research to prove that the proposed intumescent coating thicknesses and products selected will perform to their required fire resistance ratings. Working with a fire protection engineer and a representative from Carboline, we have established a paint thickness that will protect the column from reaching its yield point of failure beyond 2 hours. The process for creating this thickness is described in supporting documents as listed below including a letter from a fire protection engineer (4.1). Please reference Detail 5 (4.2) for the plan section of the described column.

4.1 Letter from David Gessert, fire protection engineer
4.2 Detail 5 I-Section “Double E” column plan section
4.3 Carboline Product Data: Thermo-Sorb VOC PDS-fireproofing
4.4 Carboline Letter: Thermo-Sorb VOC PDS-fireproofing

The use of intumescent paint allows a cost effective approach to fire proofing the building and allows the original structure of the building to be exposed and expressed.
With the proposed measures listed above, we believe that the fire safety of the columns is not compromised by the alternate method proposed and equivalent performing life safety and fire protection measures are provided.