Day & Zimmermann Ranked #38 by Engineering News-Record in 2023 Top 100 Green Buildings Design Firms List

PHILADELPHIA, PA., Sept. 21, 2023 — Day & Zimmermann (D&Z), the century-old, family-owned provider of construction and maintenance, engineering, staffing, and defense solutions for leading corporations and governments around the world, was ranked #38 by Engineering News-Record in its 2023 list of Top 100 Green Buildings Design Firms. This top-tier ranking represents one of the largest jumps in this year’s list – up 52 spots from #90 in 2022.

“As a major focus for Mason & Hanger, we are pleased to improve our ranking within ENR's Top 100 Green Design industry leaders,” said Ben Lilly, President of Mason & Hanger, a Day & Zimmermann company, which provides architecture and engineering services with a specialization in energy and sustainability. 

“In our design of government facilities worldwide, we are applying our energy and sustainability expertise now more than any time in our history. Our focus on high performance buildings and renewable energy systems supports the U.S. Government’s need for energy security and reduced emissions. This is an exciting time as designers, as we create sustainable and resilient projects that will have a lasting impact in the future. Our mission of Building a More Secure World, is fulfilled as we incorporate critical elements that improve efficiency, sustainability, and resiliency in our designs for the U.S. Government,” said Lilly.

"This significant increase in rank to number 38, up from number 90 last year, is a testament to how much Day & Zimmerman has invested in helping our customers bring more sustainable and renewable energy to their customers. We’re honored to be recognized for this commitment to green design and proud of our role in helping to foster America’s energy independence in the process,” said D&Z’s Maintenance and Construction President John McCormick.

According to ENR, green building revenue jumped in 2022 with more projects seeking third-party sustainability certifications. In ENR’s report, the ‘Green Design Government Sector’ accounted for $947.3M, 10.1% of the total $9.36 billion in reported revenue in 2022.


Mason & Hanger, a Day & Zimmermann Company, is dedicated to providing architectural and engineering services, specializing in the worldwide design of secure, mission-driven facilities, proudly serving as a partner to the United States Government for nearly two centuries. As one of the longest operating A/E firms in the United States, Mason & Hanger has a rich history covering nearly 200 years. With a mission of Building a More Secure World, the Company has served the federal government on thousands of projects, in 48 states and 165 countries. Mason & Hanger is a top 250 ENR design firm and is ranked #3 for federal and #4 for military revenues among engineering firms by Building Design + Construction. For more information, visit


D&Z’s Maintenance and Construction division helps power and improve the world by safely delivering innovative maintenance, construction, engineering, and specialty services and solutions to plant and facility owners in the nuclear, fossil, solar, government sector, chemical, advanced automotive, semiconductor, and other industrial markets.


When you've been around for more than a century, you know a thing or two. At Day & Zimmermann, we take our lifetime of experience and make things better. Our 41,000+ employees help bring big ideas to life every day. We're pushing the boundaries of innovation in construction & engineering, operations & maintenance, staffing, and security & defense. And that's not all. Did we mention that we have 150+ worldwide locations with $2.7 billion USD in annual revenue? We put people to work, we protect American freedoms, and we help our customers power and improve the world. We do what we say®.