Application of the New Italian Fire Safety Code (D.M. 3 agosto 2015) to Case Study 3 Mall Enrico Danzi Luca Fiorentini Luca Marmo Vincenzo Puccia
A Challenging Application for the New Italian Fire Code In Italy last year (2015) a specific new fire safety code have been enforced by law This new act is a semi-performance based approach that is aimed to overcome prescriptive rules proved to be not completely applicable to nowadays architectures The code structure is based on BS9999 Life Risk Threat classification The fire safety code includes deemed to satisfy solution, based on largely verified design criteria and allow, on the other hand, the application of alternative solution The importance of the new code resides in the fact that if the requirements are met no complex activities (like CFD assessments against thresholds values) should be used to state the conformity Fire Mathematical Models are included to meet fire safety requirements for Alternative Solutions
The Structure of the Fire Code The Fire safety code is divided in four main sections, the first (Generalities) introduces the definitions and allow a characterization of occupants and possible fires, allowing the risk class attribution, the second (fire design strategy) is a driven process to select the performance level required to each component of the fire safety / fire protection design. This section include Fire reaction, Fire resistance of Structures, Compartment maximum allowable surface, evacuation of occupants strategy, Fire safety management, Fire Control & Suppression, Fire Detection & Alarm, Smoke Control, Firefighting Operating, Safety of technical & utility plants. A third section is dedicated to technical fire regulation addendum for specific activities (elevators, risk explosion areas etc.) The fourth section (Methods) includes the full performance based fire design methods, with reference to the most diffused international standards.
The Design Approach to the Case Study n.3 In this first step of feasibility design, the first choice was to use the deemed to satisfy solution included in the code, evaluating the use of fire models if the result of this first step would result too conservative with regard to the safety measures The first step is the risk profile assessment for the occupant typology, based on the BS 9999 classification, included in the Fire Code as a core tool, before the development of his structure, with a selective choice of international state of art standard The Occupants Risk Profile Is so related to three Risk Profiles, in a Fire Scenario: - Life Threat - Property/Heritage/Business Continuity Threat - Environment Threat
The Fire Code logic flow start with the risk class attribution and assign with a matrix approach a set of performance levels for the fire strategy design, for items from the allowed fire reaction of materials to the fire resistance of the structures, the fire suppression the smoke control the fire safety management etc. On this basis, the characteristic of the occupants of the shop could generally assumed as B and the fire growth rate can be assumed 2 or 3, depending on an overall evaluation of the heat release rate of the fire load stored inside. In a conservative approach, the Class B3 will be attributed to all occupants of the mall (obviously the employed have an awareness of the place more close to A, but the largely prevalent characteristic of occupants is B type.
1. Mall parking (Out Of The Aim Of This Work, As Per Paragraph V Additional Remarks) 2. Shops with area from below 100 m2 to above 3000 m2 B3 3. Food-court with sitting area and restaurants B2 4. Fitness club B2 5. Cinema B2 6. Technical plant (Not Included, see Vertical Design Rule Of The Fire Code as a reference) 7. Malls and atriums with varying height B3
To Evaluate the Number of Occupants in Each Area, the Reference is the Values in Tab S.4-6 of the Fire Code For the levels 0,1 and 2, with shopping areas, the entire surface of the level was considered, including the mall, with an overall coefficient of 0.2 occupants/square meter. For the Level 3 the maximum number of occupants is a design defined constraint, with 960 seats, for the food court, the office and the kids play, the reference of Tab S.4-6 of the Fire Code allow an assessment. L 0-1-2 surf.(m q) Occ. People/s quare meter Level 3 surf.(m q) Occ. People/s quare meter shops 1313 263 0.2 level 0 16072 3214 0.2 level 1 13332 2666 0.2 cinema 1299 960 seat places declared office 616 62 0.1 level 2 10390 2078 0.2 kidspla y food court 526 210 0.4 2059 1442 0.7 L1+L2 +L3 39794 7959 tot L3 5813 2936
Fire Safety Measures Selected 3.1 Fire Reaction Requirements for upholstery and furnishing 3.2 Fire Resistance for Structures 3.3 Division into Compartments and compartments surface 3.4 Escape ways designed to fulfil the requirements of maximum length, position and availability for the occupants of each level 3.5 Fire management system 3.6 Fire Control & Suppression 3.7 Smoke detection 3.8 Smoke control 3.9 Firefighting Operation 3.10 Safety of Technological & Utility network
Fire Reaction As per the table S.1-3 the performance required for fire reaction of materials will be III for the egress routes and II for other spaces for activities. For the level II the conform solution will be the material class GM3, and for level III, respectively, the material class GM2. What does that mean? This impact on the characteristics of the upholstery, carpeting's, coatings, chairs & furniture.(table S.1-6) Fire resistance minimum required 60 minutes. For the goal 6. Safeguard fire fighters while performing rescue operations or attacking the fire it s important to follow the procedures at paragraph S.2.8.2 of the code, for the secondary elements. Must be verified the vulnerability of structures (geodetic structures, membrane structures, suspended structures, façades) to fire. Escape Ways The suspended ceilings aren t a primary structure, as per the current regulation in Italy they aren t subject to a fire resistance evaluation, but, on the other hand, the Fire Code include an evaluation for the rescue teams safety. The design decision is to do evaluate the fire resistances of pans and other structures, to evaluate the collapse risk as effect of their position over a fire plume or their resistance to the hot gases from the fire.
Escape Ways To evaluate the number of occupants in each area, the reference is the values in Tab S.4-6 of the fire code, where the assessment of this value must be done. The fire safety code allow to the store manager to define a different, and less challenging, number of occupants with regard to the specific type of activity.
Horizontal MINIMUM REQUIRED Escape Ways L0-1-2 L 0-1-2 Escape way number horiz width 1200mm 1 8 0 0 m m 2400 mm level 0 17 14 11 level 1 12 10 8 9 7 6 level 2 Horizontal MINIMUM REQUIRED Escape Ways L 3 Level 3 Escape way number horiz width 1200 mm 1800mm 2400mm shops 2 1 1 cinema 5 4 3 office 1 1 1 kidsplay 2 1 1 food court 8 5 4
For the vertical escape ways the design criteria is to totally separate the flows from the 3rd level with restaurant, cinema, shop and office from the other two levels. This approach is largely based on external stairs than on smoke proof internal stairs, with the result to a number of external steel structures, but, in the other hand, the internal layout will not modified as the shop surface will result completely available with the only exception of crossing gaps. A simultaneous exodus approach was chosen, as per paragraph S.4.8-.6.1, in consideration that the levels 0, 1, 2 are a single compartment.(see S.4.7.2 n.4). Escape VERTICAL Ways MINIMUM WIDTH L3 occup tot L3 unitary width (mm/pers.) 2936 120 mm 6.4 180mm 240m m occup tot L1-2 4744 120 mm unitary width (mm/pers.) 6.4 180mm 240m m Width tot. ALL (mm) 18790. 16 16 11 8 width tot. ALL (mm) 30364. 22 26 17 13
Fire Control An automatic fire control system based on sprinkler technology will be installed in all areas, with technical requirements of EN 12845 (or equivalent standard as NFPA 13). The mall will be protected with an internal and external fire protection with fireplugs and fire hoses full compliant with a state of art standard. Smoke Detection An automatic smoke detection system will be installed in all areas of the mall, including technical areas and specific risk areas with level IV of performance as per S.7.2. The smoke detection will be compliant with commonly accepted standards, and will be integrated in the fire management system with EVAC
Smoke Control A level III of performance smoke control system will be installed, with convective smoke evacuation system on the third floor and mechanical evacuation systems on the mall on the levels 0,1,2 by mean of channels, a full detail study on the compatibility with the sprinkler system and with the mall geometry will be conducted. For the levels 0,1,2 the smoke duct will be placed on the external walls, by mean of horizontal ducts operating a forced convective smoke control from the mall gallery, and from the biggest shop areas.
Drawings...
Thank You Any Question? For specific questions on Italian Fire Code: vincenzo.puccia@vigilfuoco.it
About the Authors Luca Fiorentini is with TECSA Srl and MSC Forensic as owner and technical director Luca Marmo and Enrico Danzi are with Politecnico di Torino as Associate Professor and Phd Student Vincenzo Puccia is with Italian National Fire Corp as Senior Fire Officer (Lt.Col.)