MANUFACTURE AND TESTING OF FIRE-RESISTANT DOORS

USING DE-INKER SLUDGE OR WASTE PAPER
Report No. PA-97-3

 

TABLE OF CONTENTS

                                                                                                                                                    Page

TABLE OF CONTENTS................................................................................................................ i

EXECUTIVE SUMMARY........................................................................................................... 1

1.  project overview........................................................................................................... 4

1.1  Background................................................................................................................ 4

1.1.1    Other Identified Technologies Using De-Inker or Short Fiber Sludges....... 4

1.1.2    Rockbilt Inc. Door Core Project..................................................................... 5

1.1.3    Fire-Resistant Door Core Certification......................................................... 7

1.2  project objectives.................................................................................................. 7

2.  Prototype testing.......................................................................................................... 9

2.1  Formulation Technology.................................................................................. 9

2.2  door core manufacturing.............................................................................. 11

2.3  Furnace testing...................................................................................................... 13

2.3.1    Warm Springs Tests...................................................................................... 13

2.3.2    Rockbilt Inc. Tests........................................................................................ 14

2.3.3    ITS Laboratory Tests.................................................................................... 14

3.  TESTING BY certifying Laboratory.................................................................... 18

3.1  first round test..................................................................................................... 18

3.2  second round test................................................................................................ 20

4.  comments and recommendations..................................................................... 21

4.1  comments................................................................................................................... 21

4.2  recommendations................................................................................................ 21

5.  ACKNOWLEDGMENTS....................................................................................................... 23

     Appendices (Not included in this electronic file but

                                available upon request)

Appendix 1 - ITS Laboratory Report - Warm springs edge system

Appendix 2 - ITS Laboratory Report - georgia pacific edge System

Appendix 3 - ITS Laboratory Report - 60 - minute door test

Appendix 4 - test program photographs

 

EXECUTIVE SUMMARY

 

A technology for manufacturing cores for fire-resistant doors has been developed that has the potential for diverting de-inker wastes from the pulp and paper industry from disposal as solid waste in Washington State.  This report presents the results of prototyping and testing doors manufactured using this technology and information about the fire-resistant door industry.  Work performed on this project was conducted by Rockbilt Inc., in cooperation with Vancouver Door Company, under a contract with the Clean Washington Center (CWC).

 

Rockbilt’s technology uses de-inker sludges (DIS) that are produced during the processing of recycled paper, especially from coated papers, which typically contain clays for the glossy finish.  Production of pulp from recycled paper produces sludges and removes the ink from the sludge.   The sludge contains short wood fiber, as well as sizing agents, clays, and ink residues.  Currently, this material has few commercial recycling uses and is landfilled.

 

The Vancouver Door Company’s manufacturing facility also agreed to participate in this study.  The facility was a suitable partner for several reasons, most significantly because they manufacture fire-resistant doors using competing technologies.

 

As a prototype product, Rockbilt selected fire-resistant door cores for the following reasons:

·        the need for an innovative door core material, especially at a reduced cost;

·        relatively few competitive products in the market place (currently, only Weyerhauser and Georgia Pacific are known to produce certified cores);

·        the abundance of DIS in the northwest, which has few other value-added uses. (DIS is produced at the rate of approximately 1 ton per 5 tons of recycled, inked paper); and

·        the short product development cycle time needed to obtain necessary certifications.

 

 

 

The raw materials used to make the Rockbilt product are commonly available and generally non-toxic in both manufacture and use.

 

In order for door cores to be accepted into the fire-resistant door market, certification by Warnock-Hersey’s Intertek Testing Services (ITS) laboratory is required (Warnock-Hersey is the primary certifying lab in the U.S.).  An entire door unit consisting of the core, edge system, door skins, hardware (locks and hinges) and any special features (imbedded windows) must be certified by the laboratory.

 

Objectives for the design element of the project were formulated as follows:

·        Equipment and facility setup at the Vancouver Door plant to manufacture fire-resistant door cores using the Rockbilt DIS product;

·        Manufacture of test doors (and prototype half doors) with the same process which will be used for full scale production, in sufficient quantities to obtain representative samples for laboratory testing;

·        Pretest inspection by an ITS laboratory representative of the manufacturing process (required for full certification);

·        Confirm key manufacturing parameters to facilitate Vancouver Door in its expansion to a full-scale production line at its Puyallup plant (once the doors are certified by the ITS laboratory);

·        Prototype and full-scale certification testing at ITS laboratory in Pittsburg, California; and

·        Document all test data and findings so that interested Washington State businesses can access the technology.

 

Furnace testing of prototypes occurred at the following locations: 

1.      Warm Springs, Oregon manufacturing facility, which was equipped with a test furnace for half-height doors;

2.      Rockbilt’s Goldendale site, where Rockbilt constructed a test furnace using the Warm Springs furnace as an example; and

3.      Warnock-Hersey’s ITS laboratory in Pittsburg, California, prior to the full-scale certification tests.

 

Rockbilt determined from tests performed at the Warm Springs site that it was necessary to build a test furnace similar to the type used at Warm Springs.  Rockbilt performed a number of test burns with this test furnace.  Initial in-house burn tests were encouraging with simple core material.  For complete doors, an edge system is required to be bonded around the core material to provide structural strength for hardware (hinges and door locks).  In these early tests, however, no edge system was used.  

 

Two doors were cast using “DC-4” as the starting formula.  Vancouver Door formed the cores into half-core doors for preliminary tests at ITS.  Both systems passed the fire portion of the test but failed in the water spray, but not to the same extent.  Observations during the fire portion of the test and examination of the failed panels revealed that, although the cores survived, both edge systems failed because of shrinkage and curling.  Rockbilt revised the original DC-4 formula to the “DC-10” formula. 

 

Three doors were cast at Vancouver Door using a Georgia-Pacific edge system, assembled into full-size doors, and tested at ITS.  The selected door from the two doors sent to ITS narrowly  failed the test for 90-minute certification for the following reasons:  (1) curl of the door at the end of the fire test, which promoted disbondment from the certified edge system; and (2) collapse of the door during the water spray portion of the test (only 7 seconds from passing the test).  On this basis, Rockbilt decided to perform one last burn test on the remaining door, seeking 60-minute certification rather than 90-minute certification.  This test was successful and the door passed both the fire and hose stream portions of the test.

 

1.  project overview

1.1       Background

 A new recycling technology for manufacturing cores for fire-resistant doors has been developed by Rockbilt Inc., located in Goldendale, Washington.  This technology has the potential for using significant quantities of de-inker sludges (DIS) in the manufacture of fire-resistant door cores. These sludges are currently produced during the processing of recycled paper and are disposed of as solid waste in Washington State.  This report provides information about fire-resistant doors and presents the results of prototyping and testing of doors manufactured using this technology.  Work performed on this project was conducted under a contract with CWC, in cooperation with Vancouver Door Company. 

 

1.1.1       Other Identified Technologies Using De-Inker or Short Fiber Sludges

Another product with similar potential has been in limited development.  Two-Forty Corporation, located in Bellingham, Washington, has developed a technology for using short fiber paper pulp sludge or mixed waste paper, combined with a mining byproduct and a proprietary binder, which can be formed into various shapes.  This patented formulation is significantly different in composition and preparation than the formulation developed by Rockbilt.  Although the technology has been available for a number of years, there has been no full-scale commercialization of products using this formula.

 

Warm Springs Indian Reservation (in Oregon) reportedly produces a similar fire-resistant door core product based on a formulation similar to the Two-Forty Corporation formulation.  In addition, Warm Springs produces an edge system that has been certified for fire-resistant doors.  This edge system was considered for manufacturing the fire-resistant doors produced during this project. 

 

In 1994, as part of the early development of their formulation, Rockbilt retained the Regional Information Center at Gonzaga University to perform a literature search for potential projects similar to this project.  The search did not yield any applicable findings.

 

1.1.2       Rockbilt Door Core Project

Over the last several years, Rockbilt has developed new binder technology that is able to produce relatively low-cost, lightweight, strong, and moldable or castable materials using diverse materials as fillers.  Rockbilt decided to formulate this recycled-content construction material using waste products from Washington State industries.  This product, herein referred to as “Rockbilt product,” is a viable technology for manufacturing commercially attractive, low cost building materials.

 

As a first round prototype, Rockbilt selected fire-resistant door cores for the following reasons: 

·        the need for an innovative door core material, especially at a reduced cost;

·        relatively few competitive products in the market place (currently, only Weyerhauser and Georgia Pacific are known to produce certified cores);

·        the abundance of DIS in the northwest, which has few other value-added uses. (DIS is produced at the rate of approximately 1 ton per 5 tons of recycled, inked paper); and

·        the short product development cycle time needed to obtain necessary certifications.

 

The raw materials used to make the Rockbilt product are commonly available and generally non-toxic in both manufacture and use.  During preliminary formula development, Rockbilt evaluated many different potential components, such as mixed waste paper, short fiber pulp waste, DIS, brown/green glass cullet, and flyash.  These were tested and considered for use as principal ingredients in the formulation.  Rockbilt focused its development efforts on DIS and mixed waste paper generated by the paper recycling industry. 

 

The original Rockbilt product formulation, DC-4, containing 40% - 50% recycled waste products (20% - 40% DIS by weight), had a number of inherent advantages as a building material:

·        the material had low density, ranging from 25 to 50 pounds per cubic foot (average of 31 lb./cu. ft.), depending upon the formulation.  Low density is favorable for shipping and handling the products as well as reducing door hardware stress;

·        the material did not burn, support combustion or spread flame;

·        the material could be optimized for a high “R-factor” (an insulative value indicating low thermal conductivity), providing good insulative properties to minimize the use of additional insulation in building systems.  The R-factor ranged from 1.0 to 2.0 per inch, with an average of about 1.8 per inch;

·        the cured material had acceptable compressive strength and was expected to pass strength tests for fire-resistant door applications;

·        with the high proportion of inorganic material in the formulation, the material did not rot or become susceptible to termites or other wood-eating insects;

·        the material had good to excellent screw and nail holding capability;

·        the material had excellent paintability;

·        the material had low sound transmission compared to brick, gypsum, or wood;

·        the material was easily mixed, molded, or cast using readily available concrete or mortar handling equipment;

·        the material could be cured and hardened without additional mechanical effort;

·        the high water content of the DIS was favorable for the proprietary binder system; and

·        because it was composed of nominally 40% to 45% by weight (wet basis) recycled waste products, the material could be inexpensively manufactured.

 

Rockbilt recognized that the characteristics of lightweight, fire-resistance, and easy castability of the material could allow door-manufacturing companies to control their own supply of fire-resistant door cores.  The readily available supply of dry Rockbilt product mix, combined with the capability of in-house casting, would reduce reliance on distant suppliers, and the company could produce the specific quantity of door cores on a just-in-time (JIT) basis.  Alternatively, Rockbilt could utilize its factory space at the Goldendale site to produce finished cores on a JIT basis for users in the Northwest, in addition to making dry mix.  This commercialization strategy could provide significant advantages for door manufacturing companies who do not want to manufacture their own door cores, but prefer to receive cores on a JIT basis to reduce overhead expenses.

 

The Vancouver Door Company’s manufacturing facility in Puyallup, Washington, agreed to participate in this study.  Vancouver Door was a suitable partner for several reasons, including:

1.      As a large door manufacturing plant, they manufacture fire-resistant doors using competing technologies;

2.      Their plant had the necessary equipment and space and their staff could provide technical feedback on manufacturing methods;

3.      They had the marketing expertise to sell the new doors upon meeting certification requirements; and

4.      They were willing to host the demonstration and were interested in making certified doors when the project was complete.

 

1.1.3       Fire-Resistant Door Core Certification

In order for door cores to be accepted into the fire-resistant door market, certification is required by Warnock-Hersey’s ITS laboratory.  Certification consists of inspections at each step of door manufacture prior to actual burn testing.  An entire door unit consisting of the core, edge system, door skins, hardware (locks and hinges), and any special features (imbedded windows) must be certified by the laboratory.  A registered Civil Engineer representing the ITS laboratory witnessed the entire core production process at the Vancouver Door Company facility.  The engineer’s P.E. stamp was placed on all doors approved for testing.

1.2       project objectives

The objectives originally identified to meet the scope of this project were to:

·        Equipment and facility setup at the Vancouver Door plant to manufacture fire-resistant door cores using Rockbilt DIS product.  

·        Manufacture of test doors (and prototype half doors) with the same process which will be used for full scale production, in sufficient quantities to obtain representative samples for laboratory testing;

·        Pretest inspection by an ITS laboratory representative of the manufacturing process (required for full certification);

·        Confirm key manufacturing parameters to facilitate Vancouver Door in its expansion to a full-scale production line at its Puyallup plant (once the doors are certified by the ITS laboratory);

·        Prototype and full-scale certification testing at ITS laboratory in Pittsburg, California; and

·        Document all test data and findings so that interested Washington State businesses can access the technology.

 


2.  Prototype testing

 

Although Rockbilt developed a product formulation that it believed would be suitable for manufacturing fire-resistant door cores, product prototyping was necessary before performing the certification testing.  The high cost associated with each certification test demanded that sufficient prototypes be initially tested at Rockbilt’s Goldendale site (at lower cost) to make minor modifications to the formulation and the manufacturing process to improve the product.

2.1              Formulation Technology

During preliminary development of the formulation, Rockbilt considered DIS among the suitable materials.  DIS is commonly considered a waste, but is actually a potentially useful material.  Use of DIS was preferred because the material was already pulped, had a high water content, and was readily available from Washington State pulp and paper companies.

 

DIS consists of nearly odorless paper fibers, clays and various ink residues, and has a light to dark gray color.  Although its physical properties and appearance vary somewhat depending on the de-inker plant of origin, the process used, and the nature of the paper being recycled, DIS is abundant and has properties similar to paper mache.  Rockbilt found that adding DIS to its binder system, especially when combined with low-density inorganic fillers, produced a lightweight, strong, and castable solid material.  It had a density of approximately 30 pounds per cubic foot, no shrinkage either on casting or curing, an insulative value approaching R = 1.8 per inch, and was extremely fire-resistant. 

 

In addition, this castable material was easy to work with.  It had the ability to produce an exact copy of any shape and/or texture that was in the mold, including such “exotic” shapes as log walls, shake roofs, tiles, etc.  The material could be colored to look like wood, coated to look like brick, or varnished.  Further, this material can be cast against an expanded polystyrene (EPS) surface with excellent adhesion.  This composite material combined the strength, fire resistance and beauty of a near-perfect copy of a mold, with the lightness and highly insulative characteristic of expanded polystyrene. 

The approximate proportions in the initial formulation of the product are as follows:       

·        DIS - 20% to 40% by weight (wet) depending upon specification

·        Inorganic filler - 15% by weight

·        Proprietary inorganic cement binders and plasticizer - 45% to 65% by weight

 

An early task of the in-house system testing program was to select a sole source DIS supplier for the first commercial formula.  Factors considered included not only the ability to conduct the fire tests, but also willingness to meet the project needs, such as transportation, freshness of DIS, ease of mixing DIS into the formulation, water content of the DIS, and compatibility with the binder system.  Initially, DIS feedstock sources were tested from:  (1) The James River Company plant in Halsey, Oregon; (2) the Stone Consolidated plant in Tacoma, Washington; and (3) the Daishowa Company plant in Port Angeles, Washington.  Evaluation of the test results led Rockbilt to conclude that the DIS from Halsey, Oregon was best suited for its needs.  The Halsey DIS is obtained from de-inking office waste paper from recycling activities in Washington and Oregon.  Properties of that DIS are shown in Table 1:

 

Table 1             Properties of DIS from Halsey, OR

                          Color:......................................................................... Light Gray

                          Dispersion in water:..................................................... Excellent

                          Clay Content?:..................................................................... Yes

                          Fiber Length:..................................................................... Short

                          Bulk Density........................................................... 32-36 lbs/ft3

                          Filler Value................................... 1.01 cm3/gram (0.0162 ft3/lb.)

                          Moisture Content:........................................................ 45-55%

                          pH (10% slurry in water)..................................................... 5-6

 

Having selected the Halsey DIS, it was possible to begin developing new formulations and core construction methods, which would improve the resistance to water spray, while preserving the excellent insulative characteristics.  As a result, the formula “DC-4” was obtained, which had 14.7% wet weight percent DIS (14% by volume of dry material).  Table 2 shows the properties of the wet DC-4 mix and the physical properties of the cured core casting.

 
Table 2          Properties of Rockbilt  DC-4 Formulation

 

Dry Mix

Wet Mix

Cured product
  Color

Beige

Beige

Beige
  Density

20 lb/ft3

7.88 pounds/gallon

36 lb/ ft3

  Mix Ratio:
   Rockbilt powder

2.9 parts by weight

N.A

N.A.
     Water

2.9 parts by weight

N.A

N.A.
      Halsey DIS

1.0 part

N.A

N.A.

2.2       door core manufacturing

For the certification portion of the test program, each door core was mixed and cast individually.  For each door, 20.9 gallons of mix were needed, so excess formulation (about 5%) was prepared each time.  The following casting technique was used for casting full-size doors at the Vancouver Door plant:

Step 1:  Place 33,583 g water in mixing vessel. 

Step 2:  Weigh out 6,357 grams of Halsey DIS, and add it to the water.  Stir vigorously with a power stirrer and a blade that produces strong shearing forces, until the slurry is as homogeneous as possible.

Step 3:  Add 36,831 g of the combined Rockbilt powdered ingredients while stirring vigorously.  Stir until a homogeneous slurry is obtained.  The quality of the finished core depends on achieving a smooth and lump-free mix.  (Note:  Each individual component of the Rockbilt mix was weighed separately and observed by the ITS engineer, Mr. Martin, during mixing in this test.  However, in practice, the formula would be pre-mixed at the Rockbilt plant.  (For proprietary reasons, the individual ingredients are not listed here.)

Step 4:  Cast the slurry into the door core mold, which has been prepared by spraying all contacting surfaces with a mold release agent such as those trademarked WD-40ä or Pamä.  Work and distribute the material in the mold to assure that the edges are solid and that air bubbles are minimized (Note: Air bubbles do not impact the fire-resistant features, but may impact the final core strength).  When the casting is complete, screed and trowel the top surface smooth and level.  Allow to stand in the mold for 1-2 hours. 

Step 5:   Remove the cast core from the mold and place in a warm, low-humidity area to dry.  The cores will lose almost 50% of their original cast weight upon adequate drying.  

The technique of removal of the “green” core from the mold will vary depending on the mold design.  One simple technique is to remove the sides of the mold and, using the mold bottom as a reinforcement and guide, stand the assembly up on its edge, letting the green core slide gently down until it contacts the floor surface.  With the core in the vertical on-edge configuration, gently separate the mold bottom leaving the core freestanding on its edge.  If it is necessary to move the green cores before curing and drying is complete, the move should be delayed as long as possible.  Although they gather strength rapidly, they are quite heavy when wet. It is desirable to allow the cores to lose as much water as possible before moving, to minimize core damage.

 

Drying of the cores is best accomplished with the cores in the edge position, with good air circulation around the piece.  If possible, the cores should be turned at least once to avoid asymmetrical drying and possible warping.   Drying time will vary depending on temperature, humidity, air circulation, and drying room configuration.  A drying room temperature of at least 20 °F above ambient, along with good circulation, will greatly assist rapid drying.  Temperatures above 150 °F should be avoided to prevent too rapid drying, warping, or cracking. 

 

Having completed the casting process and receiving the ITS inspection stamp, the cores were allowed to stand and dry at Vancouver Door for a two-week period at room temperature

(45-60 °F).  During the last five days of that period, they were treated with forced ambient air from a small floor fan.  This treatment was not sufficient to bring the cores to equilibrium moisture levels, as they were still losing about 1 pound per day of moisture through evaporation.  Calculations indicated that they had lost about 90-93% of the needed water.  Again, in the presence of the ITS inspector, it was decided that because of limited time and budget, three doors would be built, attempting to finish the drying process with the completed doors. 

 

The dry cores were cut to shape, sanded to correct thickness, and edge systems applied.  The edge system selected was the Georgia Pacific “Firestop II” system.  Appendix 3 shows the construction of the door and provides the dimensions of the components.  The doors were constructed and allowed to remain at the Vancouver Door Company for five more days.  They were then removed to the Rockbilt facilities in Goldendale, placed in a hot-room at over 100°F, and kept for 25 more days prior to the final burn test. 

2.3       Furnace testing

During development of the formulation, several preliminary fire tests were performed.  These bench mark tests utilized modifications of ordinary lab apparatus and 12" x 12" x 1" panels were sufficiently encouraging to warrant proceeding with full-scale development. The apparatus used and the results are shown in Appendix 1.  

 

Extensive prototype testing was conducted on the Rockbilt product door cores.  Furnace testing of prototypes occurred at the following locations: 

1.      Warm Springs, Oregon manufacturing facility, which was equipped with a test furnace for half-height doors;

2.      Rockbilt’s Goldendale site, where Rockbilt constructed a test furnace using the Warm Springs furnace as an example; and

3.      Warnock-Hersey ITS laboratory in Pittsburg, California, prior to the full-scale certification tests.

 

2.3.1       Warm Springs Tests

The first step in the prototyping phase was to make and test larger panels under conditions more representative of actual fires.  Rockbilt sought assistance for this at the existing burn test facilities in Warm Springs, since their certified edge systems were under consideration for use in the Rockbilt fire-resistant doors.  Warm Springs agreed to test 20" x 20" samples constructed at the normal fire door core thickness (1.6").  Testing was performed at their facility.  While the Rockbilt panel’s ability to resist heat transmission was above average (reportedly the best sample that Warm Springs had seen), the impact of the ensuing water spray portion of the test was great enough to destroy the sample after the 90-minute heating period.  The results of the Warm Springs test demonstrated that Rockbilt’s initial formulations were not sufficiently robust. More significantly, Rockbilt also realized that a number of test burns would be required to adjust the formulation to produce satisfactory results.

 

2.3.2       Rockbilt Tests

Rockbilt determined from the Warm Springs test that it was necessary to build a test furnace similar to the type used at Warm Springs.  This furnace was constructed in Goldendale by July 1996.  The furnace was capable of following the certification testing temperature protocol of ASTM E-152 on 20" x 20" samples.  The internal temperature of the fire-exposed surface was measured with a thermocouple attached to the center of the exposed test panel, while the outer

temperature was measured with a conventional infrared “heat gun” (remote optical sensor) from a distance of several feet.  Rockbilt performed a number of test burns with this test furnace using DIS from the Stone Consolidated mill of Tacoma, Washington.  A sample of this is shown in Appendix 2.

 

Initial in-house burn tests were encouraging on the core material itself, without any edge system.  With DC-4 as the starting formula, Rockbilt progressed to a demonstration casting of two doors at Vancouver Door in Puyallup.  During the handling of these first cores, one of them fractured prior to adding the edges and skin.  Rockbilt cast two more half-door cores at its Spokane laboratory, dried them to constant weight, and then shipped them to Vancouver Door for door unit assembly.

 

2.3.3       ITS Laboratory Tests

Vancouver Door formed the cores into half-core doors for preliminary tests at ITS.  Since the test was only preliminary, inspection of the casting process or the gluing of the door was needed.  Vancouver Door fitted each half-door core with an edge system and a 1/8" birch veneer skin, using their standard Borden polyvinyl acetate glue.  The edge system was attached using a Radio Frequency (RF) heating oven/press.  The skins were applied with the same glue, and their standard press was used to bond the skin to the rest of the assembly.  The half-doors were constructed as shown in Table 3, which also includes the burn test results.  The ITS test furnace was under the supervision of Mr. Fred Stumpp. 

 

Table 3        Half-Door Burn Tests
Number
Core

Edge System

Edge Binding

Results:

Half-Door #1

DC-4

Warm Springs

1/2" Birch

Passed Fire/Failed Water Spray