Something's finally cooking at the National Products building, the long-vacant restaurant-supply showroom in Old City known for its orange glazed-tile facade and stainless-steel signs.

After more than a decade of failed proposals to develop apartments or condos at the Art Deco landmark near Second Street and Elfreth's Alley, a developer has applied for permits to begin dismantling the site for construction.

Planned are six stories of apartments in a structure that incorporates the historically protected 57-year-old facade.

It's at least the fourth long-dormant Old City residential project to show recent signs of life in the still-scruffy corner of central Philadelphia where developers are responding to resurgent interest from prospective residents.

"It's really a change in market conditions," said Job Itzkowitz, executive director of the Old City District, a business association. "Neighborhoods go through cycles."

The four projects would add 670 apartments to a neighborhood that had 2,624 housing units in 2013, according to the most recent U.S. census data for the tract bounded by Vine, Seventh, and Chestnut Streets and I-95. That was up from 1,900 units in 2000.

The flurry of residential building comes as the area sheds its reputation for raucous nightlife, which scared away some of those first drawn to its red brick homes and converted industrial buildings.

It also doesn't hurt that monthly Old City rents are 11 percent lower than in the more established residential areas to the west of Broad Street - $1,990 vs. $2,251 in August - according to the most recent data from real estate website Zillow.

A half-block south of the National Products site, PMC Property Group - perhaps the city's biggest residential landlord - is seeking approvals for 10 stories of apartments beside a historic cobblestone lane called Little Boys Court.

Developers have been targeting that site since a hotel was proposed there in the late 1980s. The most recently scuttled plan was for a residential building, abandoned after its developer, Michael Yaron, went to prison in 2012 over a kickback scheme in New York.

At 401 Race St., Florida-based Priderock Capital Partners is preparing to clear the former site of the Pincus Bros.-Maxwell clothing factory to build a 216-unit building.

The last proposal at that site, sandwiched between the U.S. Mint and a Benjamin Franklin Bridge on-ramp, was New York developer Robert Ambrosi's 2010 plan for a hotel with a ground-floor music venue. It fizzled out in later years as Ambrosi was foreclosed on over his 10 Rittenhouse Square condominium project across town.

And at 205 Race St., developer Brown Hill has started work on a sleek, 17-story glass and metal residential tower it's calling The Bridge on land it acquired 14 years ago.

Developers in Old City are responding to demand from Center City's growing class of young professionals, who have the money for a nice pad but can't or don't want to buy a place, said Jeffrey Brown, a Brown Hill partner.

"What Old City is experiencing is part of what Philadelphia is experiencing, which is a resurgence of sophisticated residents that have been underserved," Brown said.

The National Products' building's presence on Second Street dates to 1929, when founder Harry Caplen bought his first property there using proceeds from selling distillery equipment to bootleggers during Prohibition, grandson Neil Caplen said.

As his food-service-supply business grew, Harry Caplen expanded to adjacent buildings, eventually occupying the site's current footprint of nearly 200,000 square feet.

Crews finished erecting the trademark orange-tile facade in 1958, according to documents filed with the Philadelphia Historical Commission. Harry Caplen had wanted to unify his growing complex of buildings behind a single facade bold enough to draw customers away from the area's competing restaurant suppliers, Neil Caplen said.

"He turned it into a landmark," he said.

National Products operated until 1996, when economic pressures forced the Caplen family to shutter the business. Since then, it's sat mostly vacant, outside of a few stints as a venue for theatrical performances during Philadelphia's yearly FringeArts Festival.

Over the last 12 years, the Historical Commission has approved at least five residential projects at the site, though none has taken root until now.

The $23.5 million proposal envisions a 192-unit apartment building with lower-level retail and underground parking. The facade will be dismantled and rebuilt to enclose the building's lower stories.

Licenses and Inspections staff are reviewing an application by the building's owner, Patriot National L.L.C. of Darien, Conn., to begin demolition at the site, Commissioner Carlton Williams said in an email.

Itzkowitz, of the Old City District, said the interest by developers is evidence of the neighborhood's resurgence. "People are being reminded what a great place it is to live, how convenient it is," Itzkowitz said.