General Building Information

Building Name: Helios Plaza

Location and Site: 201 Helios Way, Houston, TX

Building Occupant Name: BP

Occupancy: Office, Conference Center

Size: 423,500 GSF

Number of Floors: 6 floors above partial basement

Primary Project Team:

Owner – BP
Architect – Gensler
CM – Bovis Construction Ltd
Structural – Walter P. Moore & Associates, Inc.
MEP – I.A. Naman + Associates, Inc.
Elevator - Persohn/Hahn Associates, Inc.
Security - CPP and Associates
Combined Heat and Power Plant - Turbine Air Systems

Construction Dates: February 2007 - September 2009

Actual Cost Information: Withheld by owner

Project Delivery Method: Design-Build via 5 company RFP

Architecture

Architectural Style: Modern

The project is 6 stories of mixed open office with 3 stories devoted to open trader flooring. There are cafes conveniently located on every floor in addition to a Starbucks in the lobby. The building houses a conference center and has a separate parking structure for 1,909 spaces. Helios Plaza was designed to meet the highest standards of LEED and achieved a LEED platinum rating through energy and resource conservation and conscientious construction practices.

Codes:

IBC 2003
UPC 2000
UMC 2000
NEC 2008
IFC 2000
State of Texas Accessibility Standards (TAS)
2008 City of Houston Commercial Energy Code (ANSI/ASHRAE/IESNA 90.1 – 2004
ASME/ANSI A17.1-1)

Zone: Energy Corridor Management District (aka Harris County Improvement District #4)

Building Enclosures

Building Facades: The building is 100,000 ft2 of Unitized Curtain wall on four sides.The vision glass is 1 ¼” insulated, low E laminated glass with:

A minimum visible transmittance of 62%
A maximum shading coefficient of 0.32
A maximum U value of 0.25
A maximum visible reflectance of 10%

Passive aluminum shading devices surround the building.

Roofing: High Reflectivity, flat PVC membrane. The membrane is mechanically attached with fasteners and plates that penetrate through the 6" insulation to the roofing substrate.

Sustainability Features

Water Harvesting: 400,000 gallon cistern to collect rain water,
groundwater, and condensation from various sources. The amount of alternative water collected amounts to 1,550,000 gallons per annum, a 64% potable water savings. There is also a 60% water use reduction for irrigation. Overall, the water savings total to 80.1%.

Site Utilization: 55% of the site area is covered with native and or adaptive planting. This means that there is more open space than the building footprint. Of all the parking offered, 93.45% of the spaces are covered.

Energy Savings: Helios Plaza performs 34.1% better than the ASHRAE 90.1, 2004 standard. It achieves this by having 2.5% on site renewable energy and it’s own 5 MW natural gas turbine generator to generate the rest. The waste heat from the combined heat and power system helps drive the chillers for cooling. It also saves energy by being 98% covered in cool roofing.

Construction Practices:
20% recycled content materials
20% regional materials
50% FSC certified wood
95% construction waste recycled

Construction

Extensive dewatering of the site was necessary before excavation could begin on Helios Plaza. The natural land types in the Houston area vary between swamp, marsh, prairie, and forest. The project site size is 489,009 SF with 205,210 SF being left open for green space. The main contractor on the project was Bovis Lend Lease which has an exclusive partnership with the owner, BP. The design contract was awarded to Gensler after a select group of five companies were issued requests for design.

Electrical

The building is supplied with 3φ 208Y/120V service voltage. Helios Plaza has its own combined heat and power plant that supplies the building with electricity generated from natural gas. The building allocates this energy through seventeen power distribution units. In addition its own generated energy, the building is linked into the city grid and draws power from both sources. Due to the building’s function as an IST center, the need for an emergency power supply is address doubly as a precaution. Helios Plaza has two separate uninterrupted power supply systems independent of each other, both with 3-500kVa modules.

Lighting

To supply the occupants of the building with ample working conditions, an aggressive lumen scheme was developed for optimum viewing capabilities. To achieve this goal, the majority of the lighting fixtures are direct/indirect pendants. In addition to artificial lighting, most of the building is naturally lit during normal business hours. 82% of the regularly occupied spaces are day lit, which is due in large part to the 100,000 SF of unitized glass curtain wall on all four sides.

Mechanical

Helios Plaza is run through a variable air volume system. The building is equipped with 110 roof mounted and 158 under-floor terminal boxes that are distributed amongst the twenty-nine vertical air columns that pass through the floor systems. Special air handling units are installed in the computer rooms to cool the power distribution units and to vent the large amounts of heat generated by the machines. The building is cooled with blast chillers that are located in the combined heat and power plant’s separate structure. The waste head from the CHP is used to make the chilling process more efficient. Indoor air quality is a priority for the owner and an exchange rate of 555,550 CFM is implemented.

Structural

The foundations are spread concrete footings that are typically three feet below the column or wall they are supporting depending on where they are located. Basement walls only occur in the south-west corner of the structure where there is an underground tunnel that links the parking deck to the IST building. The foundation strength is 4000 psi for the spread footings and 6000 psi for the basement walls.

Two main floor systems dominate the layout of Helios Plaza. A vast majority of the flooring consists of one-way pan joist slabs and the second auxiliary system is composite decking. Pan-joist slabs are used at every level except level one where there is a slab-on-grade that also relies on grade beams for strength. The joists frame into girders that transfer to 24” square concrete columns. Composite deck is used on the double-story trading floors because long span, castellated beams are in place to reduce the weight to span ratio. Two-way slabs are used in underneath mechanical rooms and restrooms to distribute the potentially variable loads to the frame.

Lateral loads are resisted with a normal concrete moment frame. Girders span in the same direction as the pan joists to create these frames in the East-West direction. For the skip levels at trading level, large circular HSS members transfer loads from the façade to the floors above and below as well as horizontally to the concrete moment frames.

Regular girders are used to span bays up to 30.5’. Post-tensioned girders are used to span distances up to 45’. Castellated, wide flange beams are used to span distances up to 60’.

Fire Protection

Helios Plaza is classified as category B building by the IBC 2009. As such, there are no specific, mandatory automatic sprinkler systems mandated, but by City of Houston fire code, sprinklers are required. Trader floors exceed the maximum square footage for non-sprinklered by over 16,000 SF.

Vertical Transportation

There are a total of seven elevators in Helios Plaza. Six provide transport for the building staff while the seventh elevator is for services. All six normal service elevators are located in a core along the south wall of the building and each has a capacity of 3500 pounds and can reach speeds of 350 feet per minute.