Compliance Report for FEED – New Port Control Tower for QE

Compliance Report for FEED - New Port Control Tower for QE

iFluids Engineering and Consultancy WLL prepared Compliance Report for the FEED New Port Control Tower in the Ras Laffan Port of Qatar Energy. Compliance reports are a critical tool for ensuring that companies are operating in a safe and responsible manner. Click valentime dating site sign up new account to read more on, What is Compliance Report ?

Qatar Petroleum (QP) wants to build a New Port Control Tower in the Qatari city of Ras Laffan Industrial City.  Pell Frischmann (PF) has been appointed by QP to complete the FEED (Front End Engineering Design) for the said project.  The PF scope of work and deliverables are spread across two phases, Phase 1A and Phase 1B.  The Phase 1A scope of work includes the site selection process and the preparation of the discipline design briefs. The Phase 1B scope consists of the preparation of the project FEED deliverables, and covers the Concept and Detail Design.

In an effort to safeguard occupants of the New Port Control Tower and to protect the building in the event of a catastrophic event, the design of the Ras Laffan New Port Control Tower has been developed in accordance with the applicable chapters of the NFPA 101, Life Safety Code requirements.  This document details the chapters of the NFPA 101 code requirements identified as being applicable to the design.

A New Port Control Tower is proposed for the Ras Laffan Port. The primary functions of the control tower are to manage the safe operation of the port, and to provide emergency response and search and rescue services in the event they are needed.  The control tower has been designed with five occupied levels and an accessible roof top.  Building levels have been designed to accommodate the following services:

  • Level 1 – Harbour Administration
  • Level 2 – Harbour Administration
  • Level 3 – VVIP/ VIP Viewing Area and Meeting Room
  • Level 4 – Emergency / Search and Rescue Centre
  • Level 5 – Vessel Traffic Centre and Port Control Station
  • Roof Top – VTS equipment, cameras, radars, antennae and the like

An extended unoccupied center core section of approximately 55 meters high separates the first two levels from the upper three levels.   

NFPA 101 Life Safety Code, 2012 Edition was applied to the design of the Ras Laffan New Port Control Tower.  The NFPA Code requirements are occupancy-based, meaning that the life safety requirements set forth in the code cover a multitude of intended uses and thus the specific code requirements to be applied to a given building are based on the intended occupancy and use of that building. 

The code consists of nine core Chapters, one chapter on High-Rise Buildings and 26 chapters on specific Occupancy Requirements.  Core chapters apply to all buildings while the high rise and specific occupancy chapters apply as applicable to the type of structure and intended occupancy.  One of the Chapter establishes performance-based options that were not considered for this project.

This document details the NFPA code requirements applied to the Ras Laffan New Port Control Tower based on the occupancy definitions given in the Occupancy Chapters (High Rise Buildings) and (New Business Occupancies).  Once the occupancy of the building was established, the life safety criteria listed in the respective occupancy chapter provided a complete road map to all appropriate subchapters and core chapters to be incorporated into the design.  This defined the basic life safety concepts and the host of protection tools, systems, and features required for the occupancy and use of the building.

The objective of this document is to identify the code requirements of the NFPA 101 Life Safety Code to be incorporated into the design of the New Port Control Tower at Ras Laffan.  In determining the NFPA Criteria to be applied to the Ras Laffan New Port Control Tower Chapter , “Classification of Occupancy and Hazard of Contents” was referred to initially to establish the occupancy of the building.  Following the occupancy determination, the occupancy load and then hazard contents was determined. 

Chapters were then referred to so that the requirements for High Rise Buildings and New Business Occupancies verify compliance with each referenced Chapter, sub-Chapter, paragraph, subparagraph, and referenced codes, standards, and other documents.  Where two or more requirements applied, the occupancy chapter took precedence and where two or more occupancy chapters applied, the most restrictive requirements have been applied. Since the building contains occupiable levels greater than 75 ft (23 m) above the lowest level of fire department vehicle access (ground level in this case) the building is considered a “High- Rise Building”. 

As such, the New Port Control Tower design is subject to the Life Safety code requirements of NFPA 101 (requirements for High-Rise Buildings).  In addition, since the New Port Control Tower is equipped with a VIP and VVIP observation floor, which provides public access to the upper levels of the building, control tower has been classified as a “High Rise” and not a “Tower” under the NFPA requirements.  As such, none of the “code exceptions” allowed for “towers” have been used in the design of this building

Once the occupancy was set, the applicable occupancy requirements were identified and the applicable Chapter of the Core Chapter requirements were referenced. Due to the nature of the New Port Control Tower, the Fire Protection System will be design for multi-use purposes.  The bottom two floors will be classified as Business Use and the remaining tower section will be classified as a high rise. 

Since the VIP/VVIP level will be occupied by the general public it does not meet the requirement for exception as a Tower under NFPA 101.  Furthermore, since the tower will be occupied by more than 25 people it does not meet the requirement for exception as a Tower.  Thus, in applying the code requirements of NFPA 101 to the Ras Laffan New Port Control Tower, the design cannot and does not take advantage of the concessions allowed under the NFPA code for Towers with regard to means of egress.

Key Code determinations used in the design of the New Port Control Tower include the following:

  • Multiple Use Occupancy:
    • In accordance with NFPA 101. The occupancy classification of the New Port Control Tower is a Separated Occupancy.  “Separated Occupancy” is a type of multiple occupancy in which the occupancies are divided by fire resistance–rated assemblies.  As is the case with the New Port Control Tower.  Since each occupancy designation is delegated to its own level, the floor / ceiling between levels serves to meet the fire resistance ratings required for separation between occupancies.

Occupancy classifications for the building are:

  • Level 1 – Harbour Administration – General Business
  • Level 2 – Harbour Administration – General Business
  • Level 3 – VVIP/ VIP Viewing Area and Meeting Room – Assembly
  • Level 4 – Emergency / Search and Rescue Centre – General Business
  • Level 5 – Vessel Traffic Centre and Port Control Station – General Business
  • Roof Top – VTS equipment, cameras, radars, antennae and the likes – Not Occupied

Egress

  • Means of Egress

Building Designation:  The New Port Control Tower meets the definition of a “tower” as defined by NFPA 101 which defines a Tower as, “An enclosed independent structure or portion of a building with elevated levels for support of equipment or occupied for observation, control, operation, signaling, or similar limited use.”  However, the New Port Control Tower does not meet the conditions set allowing for a single exit from a “tower” due to the following.

  • The occupancy of the tower portion of the New Port Control Tower is greater than the 25 persons limit set by NFPA 101 and thus, a single exit is not permitted.
  • The design of the tower exist enclosures do not meet the conditions of NFPA 101 (or NFPA 101B) which allow for a single exit in a tower located above a building.
  • And since the tower VIP / VVIP Level will be used by the general public, NFPA 101:  does not allow for the use the elevator as a secondary means of egress. 

Thus, the tower must comply with NFPA 101, general requirement, Number of Means of Egress which states that, “At least two ways out must be built into every building, structure, part and area where the size, number of people and layout make it dangerous for people to try to use a single way out that is blocked by fire or smoke. The two ways out of a building must be set up so that it’s less likely that both could be blocked by the same emergency situation”.

PF have reviewed this code requirement to confirm compliance and thus the safe design of the building.  The second criterion in this code requirement is that the two means of egress shall be arranged to minimize the possibility that both might be rendered impassable by the same emergency condition”. 

Since the QRA did not identify a blast overpressure scenario that could impact the New Port Control Tower the Hazard Scenarios of concern are fire (and smoke) and toxic gas release. Thus:

  1. There is no credible blast over pressure scenario that can impact both stairwells
  2. Stairwells will be constructed of a uniform concrete pour and will not contain combustible materials, thus fire in the stairwells is not a credible scenario
  3. The two stairwells will have independent ventilation system and thus smoke or toxics that enter the stairwells will be independently evacuated from the stairwells
  4. The stairwell has been designed with a 2-hour fire resistance rating on the walls to allow for the safe evacuation of the tower without compromising safe egress.

Given the above credible hazard scenarios (smoke or toxic gas release) the robust design and the independent ventilation systems within each stairwell, PF has determined that the redundancy and safeguards needed are present to minimize the possibility that both stairs might be rendered impassable by the same emergency condition.  Thus, the design with two stairwells in close proximity is acceptable and does not result in a design where there is an increased risk of the spread of smoke from one stairwell to the other.

  • Means of Egress Capacity

With regard to the location and discharge points of egress points, NFPA 101 “Exit Discharge Through Interior Building” allows for discharge through an internal level of discharge (in our case the lobby) provided all of the following are met:

  • No more than 50 percent of the required number of exits discharge through the lobby and no more than 50% of the egress capacity exits through this area.
  • The port control tower meet this criteria as it has two stairs that discharge to the lobby and four other stairs (for the ground & 1st floors) that discharge to the outside AND the egress capacity of the Ground & 1st Floors exceeds 50% of the building egress capacity.)
  • The level of discharge discharges directly outside .Confirmed:  the lobby discharges to the outside
  • The interior exit leads to an unobstructed path to the building exterior and that path is visible and identifiable .Confirmed:  The path from the exits stairs to the lobby exit is a visible, identifiable and unobstructed path.
  • The interior exit is protected by a sprinkler system
  • The entire lobby of the New Pot Control tower is protected by a sprinkler system
  • The lobby area does not have any areas below – and thus does not require any additional fire separation to the floors below.

Due to the Multiple Use (segregated Use) designation of the tower occupancy, the sizing of the means of egress is based on the following NFPA 101 requirements:

When more than one emergency exit stairwell (A.K.A. means of egress) is provided (as is the case for the New Port Control Tower design), each stairwell must be sized such that in the event of a loss of one stairwell, the capacity of the remaining stairwells is not less than 50% of the required capacity.

The emergency exit stairwell capacity is based on the Occupancy loading.  Occupancy Load used to calculate fire exit / means of egress sizing is based on the Occupant Load Factor for each floor.  Since the New Port Control Tower has different occupancy uses, the stairwells need to be sized for the largest of the following:

  • Assembly Area (VIP / VVIP area) (3rd Level) – based on the larger of the following three items:
    • If equipped with fixed seating for all occupants – Use the number of seats
    • If not equipped with fixed seating for all participants – calculate based on 3.7 m2/per person (not counting the kitchen area)
    • The maximum intended number of occupants

The total occupancy for Level 3 is the sum of the largest one of the items above PLUS 9.3 m2/person for allocated kitchen space associated with the assembly area.

  • Port Control  and SAR 4th & 5th levels (Business Use)
    • Calculate based on 9.3 m2/per person
  • Ground and 1st Levels (Business Use) – Use the larger of the following:
    • Calculate based on 9.3 m2/per person (this uses the Business Use Load Factor) OR
    • Use the maximum probable number of occupants present at any time (this uses the Special Purpose Industrial Load Factor)
  • Occupancy Load is then split between the number of stairwells such that Each stairwell can accommodate no less than 50% of the egress capacity
  • The capacity calculation will account for the act that the capacity loading is cumulative as you go down the building
  • Egress Widths

Based on NFPA 101, the stairway width per person for the New Port Control Tower will be classified as “All Others” and be required to be sized as follows:

  • stairs: 7.6 mm width/person (0.3 inches per person)
  • Level Components & Ramps 5 mm/person (0.2 in per person)
  • Exit doors are calculated for each floor using the same factors

The capacity study to be completed in Phase 1B and included in the Fire & Safety Philosophy document will document the calculations for the Egress Capacity and the Egress Width and the Life Safety Design report will document compliance with NFPA 101 Life Safety Code requirements. 

  • Emergency Response / Provision for a Shelter In Place:

Due to the industrial risks surrounding the New Pot Control Tower, the building design has included a Shelter in Place safe haven where occupants from the 1st and 2nd levels (Ground & 1st floors) can take refuge.  The shelter is designed to provide a safe haven for occupants in the case of a toxic for which it has been determined that evacuation to the muster point outside the building is to high risk. 

At such time occupants will be directed to two separate and independent SIP rooms designed for 40 people each.  Each room will have an available breathing air supply base on a capacity of 80 people for 4 hours, and will be capable of maintaining a positive pressure of 70 pa of pressure when in use.  Compressed air cylinders within the SIP facility will provide breathing air.

PF is developing a SIP Design Philosophy specific to the needs of the New Port Control Tower and will document the basis and design considerations used.

Toxic releases of H2S or Ammonia will be heavier than air and will have a tendency to settle to the ground as they disperse.  Since the HVAC intake for the upper three levels of the tower (Levels 3 – 5) is mounted under the third level (65 meter above grade), it is unlikely that toxic H2S and Ammonia vapours will pose a hazard for the intake of the HVAC system for these upper levels. 

Thus, in the event of a toxic release requiring personnel on the lower two levels (level 1 & Level 2) to take refuge in the dedicated shelter in place facility, personnel on the upper three levels will be instructed to stay where they are. In the unlikely event that elevated concentrations of H2S or ammonia are detected in the HVAC air intake for the upper levels, the system will seal off the air intake. Shutdown of the HVAC system will be a manual action.

The New Port Control Tower is being designed as a contemporary, iconic landmark tower building for installation within the Ras Laffan Port.  As identified in the HAZID and QRA reports, the nature of the port operations introduces several hydrocarbon and toxic release hazards to the occupants of this control tower.  In addition, due to the design of the building the bottom two floors are classified as a building and the remaining 3 floors are classified as a Tower, in accordance with NFPA 101. 

However, given that the VIP/VVIP Level will give people from the general public access to the tower portion of the building and the tower occupancy level exceeds 25 people, the tower design cannot take advantage of the concessions allowed for towers with regard to means of egress.

Given that the above building design characteristics have been identified and the risks / requirements managed through the identification of hazards & Effects (to be managed in the H&E Register) and through the incorporation for Life Safety Code requirements, the building design manages the loss prevention risks associated with the project and the confirmation that these risks have been appropriately managed will be verified through the ALARP determination process, when applicable.