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We’ve got you covered. Since 1924, Mahaffey Fabric Structures has been the leading provider of industrial tent rentals in North America and the Caribbean.

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Presentation on theme: "We’ve got you covered. Since 1924, Mahaffey Fabric Structures has been the leading provider of industrial tent rentals in North America and the Caribbean."— Presentation transcript:


2 We’ve got you covered. Since 1924, Mahaffey Fabric Structures has been the leading provider of industrial tent rentals in North America and the Caribbean. industrial tent rentals We supply temporary, semi-permanent and custom fabric structures for any industrial application – warehousing, construction, oil and gas, break and lunch tents, environmental remediation, transportation and manufacturing. Our structures are quickly installed and engineered to withstand harsh weather conditions.


4 API RPs 752 and 753 Siting of permanent and portable buildings – Both exclude tents and other flexible structures – Industrial tent usage increased since API RP 753 introduced strict regulations on use of portable buildings API RP 756 initiated to address the siting of tents API RP 756 – Little information on response of tent structures to… 1.Explosions 2.Fires 3.Toxic Hazards

5 API RP 756 – Blast Testing Expected to be released in August or Later 2014 – Passed second ballot – Final version being proofed API funded testing of tents to blast loads Zones in RP 756 = Zones in RP 753

6 What is an Industrial Tent? Fabric or membrane structure without rigid walls or roof Includes… 1.Pole Tents 2.Light Frame Tents – use guy wires to stabilize frame 3.Rigid Frame Tents – Use moment frame structures covered with fabric Stressed or not 4.Multiple other types of temporary structure

7 Traditional buildings increase hazard to occupants if damaged in explosion  Debris from damage or collapse amplifies this hazard Tent material is lighter - Portion of blast wave passes through fabric to interior Reflected pressure on blast side of a tent is lower 1.Reflection factor = how tightly fabric stretched onto frame + fabric weight 2.Pressure inside tent approaches outside pressure


9 Comparison of Buildings Conventional Buildings Explosion hazard – heavy debris results in serious injury potential Toxic and thermal hazards – Almost any structure between occupant and hazard provides some protection Fabric Structures Explosion hazard – potential injuries from serious impact of rigid components or walls Toxic and thermal hazards – tent structures offer little protection and may reduce cognizance (compared to the open)

10 Outline of RP-756 1.Scope – Guiding principals similar to other RPs 2.Normative References – Only RP 752, and RP 753 are normative 3.Terms and Definitions 4.Determination of Tents Requiring Site Evaluation 5.Evaluation Processes 6.Tent Siting for Explosion 7.Tent Siting Evaluation for Fire 8.Tent Siting Evaluation for Toxic Material Release Annex A – (informative) Structural Analysis for Tents and other Soft Sided Structures

11 Scope (1 of 2) Covers… 1.Refineries 2.Petrochemical 3.Chemical operations 4.Natural gas liquids extraction & liquefaction plants 5.Other onshore facilities covered by OSHA 29 CFR 1910.119 Guiding Principles follow RP 752 and 753

12 Scope (2 of 2) “The Focus of this RP is primarily on process related hazards. However, non- process related hazards may exist which could present risks to occupants. Previous accidents have demonstrated that tent occupants are susceptible to injuries from fires originating inside the tent, from tent collapse due to extreme weather, and from falling objects. Some of these hazards are addressed by tent design standards, manufacturer’s recommendations, and local regulations.”

13 Comment on Scope Statement Check with the Local Fire Marshall or other code enforcement agencies! Code regulation of tents is not as uniform as for buildings: – Size or occupancy may require additional features – One jurisdiction requires sprinklers and fire alarm if tent structure size > 4500 sq. ft. Many tent manufactures include a warning:

14 2. Normative References Only RP 752 and 753 are listed as normative references (you need them to implement the RP): – RP 752 provides the background for hazards evaluation, which includes VCE modeling and limits on risk assessments – RP 753 provides the basis for the Zones Figure There are 13 other references provided in the document

15 3. Terms and Definitions Blast Resistant Tent – A tent demonstrated to meet the owner/operator’s criteria for blast using a detailed structural analysis and/or explosion testing. Engineered Tent – A tent designed to meet a specific design code. Ninety MPH Tent – A tent rated and certified to meet a 70-mph sustained wind and a 90-mph three-second gust of wind.

16 Definition of Essential Personnel Onsite personnel with specific work activities requiring them to be located in tents in or near process area for logistical or response purposes. The identification of essential personnel will vary with operation and work activities, including: 1.Normal operation 2.Start-up 3.Planned Shutdown Examples of essential personnel include, but are not limited to… 1.Craftspeople 2.Operators 3.Maintenance personal

17 Definition of Essential Personnel Examples of persons who ARE NOT ESSENTIAL PERSONNEL include, but are not limited to: 1.Designers 2.Timekeepers 3.Clerical Staff 4.Administrative support 5.Procurement staff

18 4. Determination of Tents Requiring Tent Siting Evaluation Tents intended for occupancy shall be included in the tent siting evaluation. A tent intended for occupancy has personnel assigned to it, or is used for a recurring personnel function Examples of tents that have personnel assigned include, but are not limited to: – Guardhouses, tool stations, maintenance shops, field operator shelters, offices, laboratories or warehouses. – Tents for fabrication, welding, or equipment assembly that can be performed remotely from the process unit.

19 Tents Excluded from the Sting Evaluation Examples of tents used for weather protection include, but are not limited to: – In situ welding, grit blasting, thermal spray aluminum application, and similar activities on installed equipment/piping – Non Destructive Testing (NDT) of installed equipment/piping – Weather Protection of piping or equipment such as vessels, compressors, turbines, etc. Examples of tents used for regulatory compliance include but are not limited to: – In situ asbestos or lead paint remediation – In situ hazardous materials abatement or decontamination – Catalyst loading and unloading – Refractory repair/installation Tents intended to meet owner/operator industrial hygiene requirements for extreme environmental conditions (e.g., where people can work in the environment for 5 minutes, but need time inside the tent for thermal recovery). Unlike the weather shelters described in 4.1, these tents may be excluded on the basis of being occupied only by essential personnel, locating the tent further away would increase extreme heat, cold exposure to these personnel.

20 Considerations for Tents Excluded from Sting Evaluation Owners/operators should consider local environmental conditions and applicable building codes when selecting, constructing, and maintaining these tents. These tents should be sited consistent with the owner/operator’s safe work practices. Owners/operators may consider the following potential hazards when siting these tents: – Proximity to flares, vent stacks, and atmospheric relief valves that could result in fire or toxic exposures – Proximity to sewers and vents that could result in fire or toxic exposures – Proximity to fire and toxic exposures – Proximity to cranes, heavy lift activities, and vehicle traffic – Obstructions to escape routes by tent components (e.g., guy wires marked/flagged to mitigate potential tripping hazard)

21 6. Tent Siting Methodology - Explosions This tent siting methodology utilizes the zones identified in API RP-753 for VCEs. All other explosion types require modeling to define blast loading on the tent. If the tent is located in Zone 3, then almost any type of tent is suitable (see Table 1 for exceptions). Tents located in Zone 1 or 2 require blast analysis to establish the blast loads at the tent location. Table 1 provides options on the types of tents that may be used in Zone 2 given the blast load. Some types of tents are suitable with structural analysis, whereas other types of tents require demonstration that the tent meets the owner/operator’s acceptance criteria. Tents located in Zone 1 may only house essential personnel.

22 The Zone Figure

23 Table Explaining Zone Limitations

24 Note for Zone Table Note allows use of a tent if the tent performance meet’s the owner’s/ operator’s acceptance criteria. Performance may be demonstrated by any of the following. – Risk Assessment – Detailed Structural Analysis – Explosion Testing

25 API Funded Testing Program to Better Understand Tent Response Testing limited to VCE hazard only – Does not address toxic or thermal hazards – Testing performed using BakerRisk’s Deflagration Load Generator (DLG) Three types of tents tested 1.Pole Tents 2.Light Frame Tents 3.Rigid Tent

26 Test Rig

27 Sample Test – 3% Propane

28 Test B06 Tent A (pole tent) (0.7psi, 52 ms)

29 Test B06 – Tent B (light frame tent) (0.7 psi, 52ms)

30 Test B06 – Tent C (pole tent w/o sides) (0.7 psi, 52ms)

31 Test B08 Tent A (pole tent) (1.4 psi, 22ms)

32 7. Tent Siting for Fire Hazards (1 of 2) Tent siting for fire hazards shall follow API RP-752 Section 7, with the following additional considerations – Specific tent hazards Melting or softening fabrics Vulnerability of occupants to flash fire Potential off-gassing and fumes – Shelter-in-place for fire is not a practical option for tents. Spacing tables not generally available

33 7. Tent Siting for Fire Hazards (2 of 2 ) Egress and evacuation for fire should address: – Time available to evacuate – The number of occupants in the tent – The number of exits, and location of exits away from the fire source – Evacuation route/distance – Fire thermal flux and duration – The tent may initially shield occupants from thermal radiation associated with external fires, allowing time for tent egress and emergency response.

34 8. Tent Siting for Toxic Tent siting for toxic material release shall follow Section 8 of API RP-752 with the following additional considerations: – The analysis may account for the reduction in potential toxic material releases when process areas are shut down and de-inventoried for the entire time the tent is occupied. – In most cases, tents are not suitable for shelter-in-place for toxic material release. Tents typically have high gas infiltration rates but specialized tents can be specifically designed to have low infiltration rates.

35 Questions? More about Mahaffey? See a Sample Draft of the Recommended Practice #756

36 Mahaffey Fabric Structures

37 Contact Us

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