Concrete Fireproofing Analysis, Evaluation and Repair Strategies
CONCRETE FIREPROOFING ANALYSIS, EVALUATION AND REPAIR STRATEGIES
April 12 - 16, 2010 League City, Texas, USA
Thomas R. Kline [email protected] 281.479.0391
Picture Courtesy of Refinery Terminal Fire Company (RTFC) Fireproofing Purpose
Maintaining structural stability and integrity of steel members and vessel/pipe supports for a defined period of time when exposed to a fire
Protection
Active Passive Picture Courtesy of Refinery Terminal Fire Company (RTFC)
2 Fireproofing Basics
Material minimum thickness Restrict heat transfer rate
Acceptable steel Protected core temperature at element the end of fire exposure to avoid collapse/buckling
3 Comparison of Typical ‘Hydrocarbon’ and ‘Cellulose’ Time-Temperature Curves
2500 1400
Hydrocarbon 1200 2000 F) C) ° Cellulose 1000 ° ( it (
Within 4 ss minutes 1500 800 ahrenhe s Celsiu FF 600 ee 1000
400 Degre egrees DD 500 200
0 0 0204060 80 100 120 Minutes 4 Effect Of Temperature On Strength Of Structural Steel
100
80 rength
60 50% reduction
riginal St @ 1000 °F 40 ent of O cc 20 Per
0 50 300 550 800 1050 1300 1550 Degrees Fahrenheit ( F) ° 5 Fire And Explosion Behavior
Resistance to thermal and erosive forces Surface temperature of substrate Non-combustible Withstand effects of explosion and subsequent drag pressures
Picture Courtesy of Refinery Terminal Fire Company (RTFC)
6 Pre-Fire Durability
Weather cycling and chemical tolerance Vapor permeability and low porosity Vibration resistance - compressive, tensile and flexural strength Hardness value and impact resistance Abrasion and erosion resistance Bonding strength Wash-down resistance
7 Passive Fireproofing Materials
¾ Heat absorbers Lightweight CEMENTITIOUS ¾ Hard and durable ¾ Economic Dense ¾ Easy to install and repair
Epoxy ¾ React under fire and emit gases INTUMESCENT based ¾ Form a low density carbonaceous char
Boards ¾ Can provide thermal insulation FIBROUS ¾ Absorb water Blankets ¾ Indoor applications
¾ Sandwich of metallic cladding, Composite COMPOSITES cementitious board, and mineral Panels or ceramic fibers ¾ Not economically feasible 8 Cementitious Concrete Materials
Made with Portland cement or modified fire- resistant cements Specific weights y Dense concrete - 140 to 150 lb./ft3 y Light wei ght concret e - 25 to 80 lb. /ft3 Thermal conductivity tends to be inversely proportional to specific weight Capable of withstanding direct flame impingement up to 2000 o F (1100 o C) Alkaline passive film protects the embedded steel
9 Intumescent Epoxy Coatings
Intumescent coatings react to flame or heat at around 300o Fahrenheit (149o C) by expanding int o a thi ck multi cell ul ar i nsul ati ng bl ank et . Thi s intumescent carbonaceous foam sharply limits the spread of flame and insulates the steel. Washable, aesthetically pleasing, mark resistant surface like traditional paint Provide protection from corrosion Require expertise in application and controlled conditions Comppygaratively higher cost to cementitious materials
10 Fireproofing Rating
A function of:
Time and ease of evacuation Fire hazard ppyosed by substance Fire suppression capabilities
2 inches (50 mm) of cementitious products will provide a 2-hour rating (BS476 & ASTM E-119)
11 Concrete Fireproofing In Processing Units
Multilevel Equipment Structures
Pipe Racks
12 Fireproofing Deterioration
Corrosion Cracking
Risk Of Loss Of Fire P rot ecti on
Efflorescence Fire Damage
13 Embedded Structural Steel Corrosion Exposed During Fireproofing Inspection Process
14 Rust Stains Emerging From Fireproofing Indicating Early Evidence Of Steel Member Corrosion
Failed Fireproofing Due To Embedded Structural Steel Member Corrosion
15 Improperly Detailed Cementitious Fireproofing, Notice No Mesh Reinforcement
16 Severely Corroded Embedded Wire Mesh And Corroding Structural Steel Member Flanges
Severely Corroded Embedded Wire Mesh And Corroding Structural Steel Members & Connections 17 Fireproofing Deterioration Mechanism Corrosion- Corrosion Induced Delamination/ Products Cracking Spalling
Cementitious Structural Steel Fireproofing Beam/Column
Surface Shrinkage Corrosion Cracking Products
18 Fireproofing Deterioration Mechanism ()(cont.)
Structural Steel Beam/Column
Preformed Inorganic Panel Fireproofing
Corrosion Open Areas Within The “Boxed” Products Struct ural M emb er Fill s With Mo is ture And Promotes Corrosion
19 Prior Repair Shrinkage Cracked And Pipe Slide Shoe “Seized” By Corrosion
20 Fireproofing Deterioration Mechanism ()(cont.)
PIPELINE
Corros ion Bu ild-Up Structural Steel Frozen Slide Corr osi on Rotation Cementitious Fireproofing
Struct ural St eel Rotation Beam/Column 21 Condition Survey And Evaluation
Assess the condition of concrete fireproofing
Evaluate causes of concrete/steel distress
Provide conceptual repair recommendations
22 Need For Fireproofing Restoration Safety y Possible structural collapse y Reduced fire protection/lower expected performance y Personnel at risk due to falling debris Insurance costs Aesthetics of damaged/falling fireproofing
23 Visual Inspection And Mapping
Note: Excavation at crack location
24 Excavation Geometry
Struct ural Steel element
Reinforcing wire mesh Structural Steel Beam
Fireproofing
Fireproofing
25 Ultrasonic Thickness Measurements
Ultrasonic Thickness MtMeter Structural steel pipes, webdbbs and beams flanges AidfAccess one side of steel member
26 Measurement Analysis
Wide Flange Flange Section
Shape Thickness tf Loss (%)
Theoretical
vs
Measured t f If critical, t w remedial actions needed before...
27 Conceptual Fireproofing Repair
Assemble scaffolding for elevated regions of distressed fireproofing Remove deteriorated concrete fireproofing and wire mesh avoiding damage to structural steel members Clean exposed embedded structural steel members of corrosion products Inspect members and connections for structural integrity Coat exposed structural steel section
28 Fireproofing Repair (Cont.)
Install wire mesh AbltAssemble mortar-tig ht cavit y f ormwork Re-establish the cementitious fireproofing section b y usi ng “f orm and pour” pl acement techniques RfRemove formwor kftiiddk after curing period and surface grind cementitious repairs to match original fireproofing surface contours
29 Valuable Repair Aspects
Turnkey investigation Attention to details Budgggpeting capabilities Corrosion protection to steel Production rates Adjustable crew size with qualified personnel High qualit y repai r mat eri al s Observe standard industry practices
30