Nathan Norman Tyson, former president and chairman of Tyson Metal Products Inc., a large stainless steel food service equipment manufacturer, died Saturday at the Weinberg Village of the Charles Morris Rehabilitation Facility in Squirrel Hill. He was 90.

Mr. Tyson, affectionately known as "pop pop" to family members, was born in the Universal neighborhood of Penn Hills, but during his formative years, his family moved to Highland Park. He graduated from Peabody High School and later attended Carnegie Institute of Technology, now Carnegie Mellon University.

Mr. Tyson spent six years in the U.S. Army Air Corps, rising to the rank of major. During World War II, he spent a year in Burma as a member of the 74th Tactical Reconnaissance Group.

After his discharge, Mr. Tyson returned to Pittsburgh.

In 1946, Mr. Tyson's older brothers, Harry and Alan, started Tyson Metal Products. Later, Mr. Tyson and two other brothers, Bill and Meyer, joined the company. Under Mr. Tyson's watch, the company expanded, employing more 300 people in three different facilities in Pittsburgh and Clearfield.

The company manufactured commercial food service equipment, such as counters and stainless steel tables and sinks for restaurants, schools and prisons.

"Our dad was proud of his business," said Mr. Tyson's son, Harvey, of Shadyside. "He loved to drive along with my mom, brother, sister and me and point out the large kitchen jobs his company had built and installed."

His son said Mr. Tyson was fond of saying: "They'll be here long after I am gone."

The company installed kitchen equipment at the University of Pittsburgh, Carnegie Mellon University, a number of Burger King restaurants around the country and the old Three Rivers Stadium.

Mr. Tyson was one of the original members of the National Association of Food Equipment Manufacturers and Food Equipment Distributors Association.

In addition to his son, Mr. Tyson is survived by a daughter, Hilary Porter, of Fox Chapel; another son, Richard, of Pembroke Pines, Fla.; four grandchildren; and two great-grandchildren.

The service and interment will be at 11 a.m. today at B'Nai Israel Cemetery, Blackadore Street, Penn Hills.