Initiates Development of Modular Construction Method for Hyperscale Data Centers

NTT FACILITIES Inc. (Headquarters: Minato-ku, Tokyo; President and CEO: Susumu Kawaguchi; hereinafter referred to as NTT FACILITIES) has begun developing a new construction method for data centers that significantly shortens the application, design, and construction periods. This method involves modularizing buildings and equipment, and constructing data centers by assembling components produced in factories at the site (prefabrication). By standardizing the process from design to construction, the period from application and design to construction for large-scale data centers of tens to hundreds of MW for hyperscalers will be reduced by up to approximately 50% compared to conventional methods.

Figure 1: Conceptual image of the data center model "Hyper Ready ModuleTM"

Overview

In recent years, the demand for data centers has been rapidly expanding, driven by the widespread adoption of generative AI and the advancement of ICT services. However, in Japan, data center construction often takes 3 to 4 years from the start of design to completion, making the prolonged design and construction period a significant challenge.

Contributing factors include the procedures based on the Building Standards Act to address Japan's unique seismic risks and compliance with local government ordinances, as well as a shortage of labor in the construction industry. Furthermore, the performance of IT servers has dramatically improved recently, leading to significant changes in server specifications during the period from design to completion. This results in frequent design modifications and re-evaluations for data centers.

In response to these challenges, NTT FACILITIES has begun developing a data center model (Hyper Ready ModuleTM) (*2) that modularizes building structures and equipment as much as possible, and constructs them by assembling factory-produced components on-site (prefabrication). This model aims to achieve a total project duration of approximately two years for large-scale data centers for hyperscalers by standardizing all processes from design to construction, with an estimated one year for application and design, and one year for construction.

Figure 2: Image of the standard model of the data center model "Hyper Ready ModuleTM"

Key Initiatives for Shortening Design and Construction Periods

1. Modularization of Buildings (Adoption of System Construction)

To shorten design and construction periods, NTT FACILITIES has entered into a basic agreement with NIPPON STEEL ENGINEERING CO., LTD. (Headquarters: Shinagawa-ku, Tokyo; President and CEO: Yukihito Ishiwa; hereinafter referred to as NIPPON STEEL ENGINEERING) and has begun examining the standardization of modular data centers using system construction methods and the realization of shorter construction times.

In this model, the five main components that make up the building (foundation, retaining wall, steel frame, exterior walls, and roof) are modularized and produced in a factory in advance to shorten the construction period. Furthermore, by placing major air conditioning and electrical equipment outdoors and making the building low-rise (approximately 1-2 stories) and lightweight, a hybrid seismic isolation and damping structure is adopted. This structure features a highly earthquake-resistant building while damping major equipment and providing seismic isolation for the floor of the data hall where IT servers are installed (floor seismic isolation). By maintaining BCP performance equivalent to that of a seismically isolated building without making the entire building seismically isolated, the application and design period can be shortened to one year, and the construction period to one year, by shortening or omitting various application periods for structural assessments and ministerial approvals, as well as the periods required for seismic isolation and foundation work.

Figure 3: Shortening of construction period through hybrid seismic isolation and damping structure

2. Modularization of Equipment

With the recent advancements in IT server performance and increased heat generation, there has been an increase in the volume and weight of piping and wiring, such as air conditioning chilled water pipes, electrical wiring bus ducts, and wiring racks. In the conventional method of supporting these from the upper floor slab, challenges in seismic resistance and constructability have become apparent, especially in data centers with high floor heights.

To address these issues, this model adopts the DfMA (*3) method, where main structural components serving as the main frame, as well as sub-frames for equipment seismic resistance (frames supporting piping and wiring, commonly known as "grape trellises"), are constructed in advance, and air conditioning pipes and electrical wiring are unitized in the factory and assembled on-site. By minimizing overhead work using lifters, prefabrication of equipment processes is promoted for increased efficiency. Furthermore, by unitizing power supply equipment (container PTU) (*4), the overall equipment construction period is shortened.

Figure 4: Unitization of sub-frames for equipment seismic resistance and air conditioning pipes and electrical wiring (adoption of DfMA method)

3. Resilience Design that Prevents IT Service Interruption (PML < 10% x Minimized Downtime) *5

This model incorporates resilience design to ensure high reliability against seismic risks. Specifically, based on the PML evaluation criteria (seismic risk assessment criteria) equivalent to Tier 4, the highest standard in the facility standards set by the Japan Data Center Council (JDCC), the following measures are adopted to suppress the impact on equipment during earthquakes and maintain data center functions:

Improved resistance by damping sub-frames for equipment seismic resistance ("grape trellises") (Figure 5-1) (Reference: Patent No. 6216552) *6

Improved seismic resistance of equipment by introducing damping materials at the connection points between the building structure and the installation frames for electrical and mechanical equipment (Figure 5-2)

Ensuring seismic resistance of the IT server section through floor seismic isolation applied to the data hall floor (Figure 5-3)

Introduction of monitoring systems for structures and equipment

Figure 5: Image of hybrid seismic isolation and damping structure

Future Plans

Moving forward, based on this model, we aim to realize shorter construction times for "Modular Data Centers for Hyperscalers (Hyper Ready ModuleTM)" by collaborating with data center operators and related organizations to materialize the concept, targeting completion by fiscal year 2028.

NTT FACILITIES will present an ideal vision for data centers from multiple perspectives, including addressing high heat generation and high density, achieving carbon neutrality, and harmonizing with the local community. By engaging in integrated efforts from design and construction to the sale and maintenance (*7) of air conditioning and power equipment, we will strive to contribute to the realization of a regional circular economy and the creation of a sustainable future while supporting ICT services.

Notes and Terminology Explanations

*1 This assumes the application of our standard design, early commencement of work through integrated design and construction contracts, and the timely delivery of long-lead items such as extra-high voltage receiving and transforming equipment. The construction period may vary depending on these preconditions, market trends, and building conditions.

*2 "Hyper Ready ModuleTM" is a trademark application pending by NTT FACILITIES Inc.

*3 DfMA Method: Abbreviation for Design for Manufacture and Assembly. A methodology based on the concept that easily assembled products require a minimum number of parts, aiming for cost reduction, minimization of parts count, and shortening of lead time.

*4 Container PTU: A power unit (Power Train Unit) that integrates transformers, main distribution boards, UPS, etc., within a container. As it is pre-constructed in factories, on-site installation time can be reduced.

*5 PML: Ratio (%) obtained by dividing direct loss amount by replacement cost. When evaluating seismic risk safety in the data center facility standards established by JDCC, the standard value for Tier 4 (highest standard) is less than 10% PML.

Downtime: The total time required from the occurrence of an earthquake until the start of repair work (resistance) and the time required for repair work (recovery). It evaluates indirect losses from both hardware and software aspects, considering factors such as lifeline, equipment, and operational mechanisms, as well as annual revenue generated by the building. Direct losses due to earthquake damage repair costs are added to this to evaluate resilience performance. (Reference: Architectural Institute of Japan, Report of the Special Committee on Building Resilience and BCP Level Indicators, March 2020)

*6 NTT FACILITIES Inc. Patent Registration (September 29, 2017) Vibration Damping Suspension Structure Using Viscoelastic Material

*7 Data center maintenance services will be provided by NTT Anode Energy Co., Ltd.