Anthony Schirripa, Chairman of Mancini Duffy, an architectural and design firm in New York.

I DECIDED at a young age to become an architect after watching my father, who had a small construction company. I wanted to learn the business, but he said that he didn’t want me to have calluses on my hands, and that I should go to college.

I attended Brooklyn Technical High School, which had an architecture program, and in the summers I was a bricklayer’s laborer at my father’s company and learned to operate a backhoe.

I started in the community college system in New York and transferred to Texas A&M, graduating in 1973 with a bachelor’s of environmental design and a bachelor’s of science in building construction.

My first job was at William B. Tabler Architects, which specialized in hotels. I stayed four years, worked briefly at another architecture firm and then ran my own firm for a year. After that, I joined an architecture group at Gibbs & Hill, an engineering company that designed nuclear power plants.

From 1980 to 1995, I worked for Gensler, another architecture and design firm, where I became a partner. One project I worked on, the Goldman Sachs building in Manhattan, was a half-million square feet. The indirect lighting for the trading floor was trend-setting.

I joined Mancini Duffy in 1995 as a partner, and five years later was named C.E.O. When Ralph Mancini retired in 2006, I became chairman and C.E.O., and in 2010 I passed C.E.O. responsibilities to Michael Winstanley, whose firm merged with ours in 2009.

One of Mancini Duffy’s most challenging projects was consolidating the headquarters for Wachovia Securities, now Wells Fargo Advisors, in the Seagram building on Park Avenue in 2005. That building is a landmark. The lobby and the first 15 feet of the perimeter had to be kept in their original form while we transformed Wachovia’s portion of the structure. We had a tight schedule. At one point I thought it might not be possible to meet the deadline, but we did.

On Sept. 11, 2001, we were located on the 21st and 22nd floors of 2 World Trade Center, the south tower. When the first plane hit the north tower, I was peering out the window at the plaza below while listening to my voicemail. A man was walking toward the north tower when he looked to his right and started running. I heard a pop, thought I smelled diesel fuel and wondered if an emergency generator had exploded in a test. (Later, I knew it was jet fuel.) I decided we should evacuate.

After all our employees left the office, I headed for the stairs. Then I recalled what happened in 1993, after a truck bomb exploded at the trade center: many of our belongings would disappear, and we’d never know what happened to them. So I returned and locked the doors. Then I took the elevator to the lobby. I’m lucky I made it out.

Once on the ground, I looked for our employees, who had all left.  I finally got a view of the south tower. Until then, I had no idea that a plane had hit it. I saw that columns were missing on the building perimeter and realized the tower might collapse. I ran into a health club and saw the news on TV.

Our company lost everything, from equipment to records, but we were up and running again in less than a week. JPMorgan gave us temporary space on Park Avenue right after the towers collapsed. And a construction company leased 30 computers for us for a month. Since then, we’ve moved to Midtown and set up more robust back-up and recovery for our I.T. operations.

We’re lucky that everyone in our firm survived. I still get emotional about all the lives that were lost that day. Occasionally, I run into someone I know from the World Trade Center. We look at each other and realize we both survived. It’s a weird feeling.