The document discusses fire protection of wood and cellulose materials used in construction sites. It describes two mechanisms by which cellulosic materials burn - thermal degradation above 300°F and smoldering combustion at lower temperatures. Fire retardant treatments can be chemical impregnations into wood or surface coatings applied as paint. The document then examines various fire retardant chemicals and their effects. It introduces EndoGel, a water-based fire retardant developed by EnTec for pre-treating combustible materials to reduce ignitability and retard fire spread during hot work activities like welding.

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EnTec
Consulting
White Paper
Protection of Wood and Celluloses Materials
For “Hot Work” on Construction Sites
By Edmund Pennartz
November 2015

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Introduction
The burning of cellulosic materials occurs by two alternative mechanisms. Temperature of 300°F (149°C) or above
causes thermal degradation of cellulose into gaseous, liquid, tarry, and solid products. The volatile, flammable gases
ignite and provide additional heat to further pyrolysed the liquids and tar into more flammable vapors, and also form
residues, mainly carbonaceous char and gas mixture containing water and carbon dioxide. This process continues
until only the carbonaceous residue is left. The second pathway operates at lower temperatures with the
carbonaceous char from pyrolysis. The oxidation of the resulting charring a slow and localized process called
glowing or smoldering combustion. Smoldering combustion may occur in the charred areas or consume the entire
area, proceeding as a front in the solid-state rather than a flame in the gas phase.
Fire-retardant treatments for wood can be classified into two general classes: (1) those impregnated into the wood or
incorporated into wood composite products, and (2) those applied as paint or surface coatings. Chemical
impregnation has the greater use, primarily for new materials, whereas coatings have been limited primarily to
materials in existing constructions. There are advantages and disadvantages to each class. Coatings are applied easily
and they are economical.
Chemical impregnation usually involves full-cell pressure treatment and can be costly. A coating is subject to
abrasion or wear that can destroy the effectiveness of the fire retardant. Chemical impregnations deposit the fire
retardant within the wood, so that if the surface is abraded, chemicals are still present. On-site application of surface
coatings requires strict control of the amount applied to ensure correct loading levels for a particular flame-spread
rating.
Both coating and impregnation systems are based on the same chemical compounds, although the formulations for
each vary.
Most of the chemicals used in fire-retardant formulations have a long history of use for this purpose, and most
formulations are based on empirical investigations for best overall performance. These chemicals include the
phosphates, some nitrogen compounds, some borates, silicates, and more recently, amino-resins. These compounds
reduce the flame spread of wood but have diverse effects on strength, hygroscopicity, durability, machinability,
toxicity, glue-ability, and paint-ability.
• Phosphates
• Carbamide
• Borax (Na2B4O710H2O)
• Boric Acid (Polybor Na2B8O13-4H2O
• Ammonium Bromide (BrH4N)
• Huntite (Mg3Ca (CO3)4
• Hydromagnesite (Mg5 (CO3)4(OH) 2·4H2O)
• Magnesium hydroxide Mg (OH)
Burning of wood
The reduction of ignitability and combustibility of wood products is based on chemical and physical means that have
an effect on different stages of ignition and burning, for example:
heat induced changes of the internal structure of wood at the molecular level; physical and chemical processes of
compounds produced in these changes, both inside the wood and in the gases formed above it;
• transfer of heat in a wood product;
• transfer of oxygen into reaction areas
• Ignition and combustion of wood
Many materials in our environment, including wood products, burn “indirectly” in the sense that the materials do not
actually burn, but combustion takes place as a reaction between oxygen and the gases released from a material (an
exception from this rule is the glowing combustion of charred wood where oxygen reacts directly with carbon).
Under the influence of heat, wood produces easily substances that react eagerly with oxygen, leading to the high
propensity of wood to ignite and burn. Ignition and combustion of wood is mainly based on the pyrolysis (i.e.
Thermal decomposition) of cellulose and the reactions of pyrolysis products with each other and with gases in the air

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mainly oxygen. When temperature increases, cellulose starts to pyrolysis. The decomposition products either remain
inside the material or are released as gases. Gaseous substances react with each other and oxygen, releasing a large
amount of heat that further induces pyrolysis and combustion reactions
Fire performance of wood
The reaction-to-fire properties, such as ignitability, heat release and flame spread, are most relevant for fire retardant
wood products. Charring as a fire resistance characteristic property may also be influenced especially by surface
protective layers.
Ignitability
In order that wood can ignite, its temperature must rise so high that pyrolysis takes place strongly enough and the
chemical reactions of combustion start. Therefore, the ignition of a wood product is dependent on the way of
heating, that is, the thermal properties of the material, and the way of heat attack on the material.
Heat release and fire spread
Heat released in combustion is the driving force of a fire: the larger the heat released by a burning object is, the
faster the fire spreads and the hotter the gases and limiting surfaces of the fire enclosure become. Thus, one of the
most essential quantities describing the burning of materials is the rate of heat release, denoted and expressed in kW
or MW.
Charring
Charring is a chemical process of incomplete combustion of certain solids when subjected to high heat. The resulting
residue matter is called char. by the action of heat, charring removes hydrogen and oxygen from the solid, so that
the remaining char is composed primarily of carbon.
Charring is an important process in the combustion ignition of solid fuels and in smoldering. In construction of
heavy-timbered wood buildings the predictable formation of char is used to determine the fire rating of supporting
timbers and is an important consideration in fire protection engineering.
Smoke production and toxicity
Smoke formed during a fire consists of small, mainly carbon containing particles that reduce the visibility. High
smoke production in the early phases of a fire is very harmful considering the fire safety of buildings, because it
endangers emergency egress through the reduction of visibility and the irritating and incapacitating effects of smoke
gases. Smoke production is dependent on the burning material, but also external factors, such as fire type (flaming /
smoldering) and oxygen supply, are important.
Fire Retardant Mechanism
Fire Retardants are broadly classified as either flame retardant or smoldering retardants. Flame retardants refer to
chemicals added so that the treaded surface/material will not support flaming combustion after the ignition flame has
been removed. Smoldering retardants refer to chemicals which effectively prevent smoldering combustion, and the
flameless combustion of material which occurs after the igniting flame is removed.
Combustion of cellulosic materials can occur in a primary mode, where visible flames are present, or in a secondary
mode, where flames are absent. In the latter case, the combustion is referred to as glowing or smoldering, depending
on whether or not light is emitted...
Smoldering combustion is the heard of the fire hazard problems due to its potential transition to flaming combustion.
While such fires are not a frequent event, they are severe and costly when they do occur

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Fire Facts
Fire represents the highest dollar loss to buildings under construction and their related materials.
Annually, residential and non-residential fires combine for an average of 476,700,000 fires per year at a cost of over
10 billion dollar on damage per year, cooking is by far the leading cause of both residential and nonresidential fires.
Also high on the list for both are unintentional fires. These are frequently started by a "hot work process" that gets
out of control.
Welding, cutting, and brazing are all examples of hot work processes. Many a fire has been started by a contractor
performing welding in a plant
Hot Work – Operations such as welding, cutting, burning, heating, grinding, or similar spark, slag, or intense heat
producing activities that are capable of igniting combustible materials or flammable atmospheres or providing a
source of ignition for a fire. Also defined as cutting and welding operations for construction/demolition activities
that involve the use of portable gas or arc welding equipment, open flame or spark-producing apparatus, to reduce
the likelihood of fire, start by controlling potential ignition sources
Introducing EndoGel
EnTec’s founder can look back of a 30 Year long history of patenting and developing fire safety and fire preventing
products and systems.
The development of a highly effective fire retardant took years in the making and is based on the aforementioned
principles and technologies.
The goal of the development of the Endo Gel was to help the construction industry as well as the “Do It Yourself”
home owner, preventing accidental fires caused by construction and repair work with open flame surrounded by
combustible materials
Welding, cutting or burning perhaps represents the number one cause of fires in cultural heritage properties, as so
many fires occur to buildings under renovation or repair. A daily hot work permit system should be established and
strictly enforced. This system should require a contractor or other person wanting to perform hot work, to have a
signed permit from a responsible staff person after it has been determined/agreed upon that: all combustible
materials are protected, this can be accomplished by covering all combustibles with fire retardant blankets such as
Endo Gel, or constantly wetting the area down, a fire watch is established this involves having a designated person
or persons standing by with a portable fire extinguisher for the duration of the work, plus half an hour beyond, to
extinguish any blazes that may start , and the area is carefully inspected afterwards to detect any fire or smoke.
• Endo Gel is a water based fire retardant for pre and post treatment of most combustible solids.
• EndoGel reduces or eliminates additional cost for “Fire Watch” personal.
• EndoGel’s use is highly cost effective (pennies per square foot).
• Endo Gel is highly effective wet as a foam and dry as a protective film.
• EndoGel penetrates natural surface by developing a self-extinguishing surface
• EndoGel adheres to any other materials without running off and builds a protective foam barrier
• Endo Gel enhances the charring of the combustible material
• Endo Gel reduces significantly smog development
Applications:
 Fire and Afterglow Retardant
 Should be used to impart fire retardant properties to a wide variety of cellulosic materials such as Paper,
Cotton, Wood, dry Grass etc. It has also the utility of a fire retardant for substrates such as Rubber and
Plastic.
 Highly effective in reducing dramatically the flammability of dry Grass and brushes and simultaneously
preventing afterglow, not available in other commonly used fire retardants.
 Lumber treatment via pressure-injection Flame Spread Index (FSI) 5
 Lumber treatment through spray or dipping process Flame Spread Index (FSI) 51
 Protective retardant-barrier for Plumbers, Construction-Workers (Welders performing “hot-work”) can be
used as an pretreatment hours before hot work or immediate application.
 EndoGel is non-toxic, non-corrosive and environmental friendly.

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References:
Bikales, N.M. Encyclopedia of ’Polymer Science and Technology”, Volume 7, Fire Retardant, John Wiley, 1967
Shafizadeh, F. “State of the Art on Smoldering Combustion”, University of Montana
Sanders, H.J. “Flame Retardants” Chemical and Engineering News 04.1978
Winandy, J.E, and E, L, Schmidt, Forest Prod, 45(2), 1995
Pennartz, E, “Fire Extinguishing and retarding Agent” 1987, German Patent # PA 3634 125, 8,
LeVan, S, L., Ross, R, J. and J.E, Winandy, Res. Papers FRL-498, USDA Forest Service, Madison WI 1988
Oberley, W, J, Coppers Co. Inc. US Patent 4,373,010, February 1983
Pennartz, E, “Class A Combustion Inhibiting Method and Composition” US Patent # 4,961,865 November 1992
LeVan, and J.E, Winandy, Wood and Fiber Science, 2 (1), 1990
Esco Mikkola, Fire Research Laboratory at VTT-Technical Research Center of Finland.1988
Pennartz, E, “Fire Mitigating and Moderating Agent” US Patent # 8,080,186 B1, December 2010
Technical Service Bulletin 102, Borax Consolidated Limited.
Service Bulletin, Borates for Fire Retardency in Cellulosic Material, Borax Consolidated Limited.
Pennartz E. Fact Sheet for protection of Wood and Wood Products with specially designed Fire Retardants.
September 2014
Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd. Edition 10, 42s
The recommendation in this bulletin is based upon information believed to be reliable. As the use of our products is
beyond the control of the manufacturer, no guarantee, expressed or implied is made as to the effects of such or the
results to be obtained if not used in accordance with directions of established safe practice. Nor is there any warranty
of fitness for a particular purpose which extends beyond the described uses in this bulletin. Furthermore, nothing
herein shall be construed as permission or recommendation to practice a patented invention without authorization of
the patent holder.
Inquiries for product data sheet, availability, pricing etc. at;
EnTec Consulting
Tel: 1 (775) 420-1034
Email: eddyentecsolutions@gmail.com