New security gadgets abound since Sept. 11.

Security is a hot topic among New York City landlords, and high-tech security is getting much of the attention. Gadgets that read ID cards, metal detectors and closed-circuit surveillance cameras are becoming fixtures at several Class A properties.

To be sure, it isn't the first time landlords have invested in high-tech security measures, but the marketplace has changed dramatically.

Just last month, a patent was issued for a product that seals off the HVAC of a building in the event of a biological or chemical attack. A protective structure that will protect glass curtain walls from bomb blasts has also been developed in recent weeks.

But established security experts have this to say: Caveat emptor.

"The trouble with these gadgets is that they fail," said one security consultant, who asked not to be named.

"They have limitations. And they may not be cost effective, at this point, to implement," said the consultant, who works for one of the largest risk consulting firms in the world.

In his opinion, biometrics--iris scanning software and thumbprint ID machines, for instance--represent the most promising high-tech security solution for building owners. Biometrics are difficult to evade, but it is cost prohibitive for owners to invest in them now.

As the marketplace expands, however, these systems will become less expensive, so it may be in the best interest of owners to wait.

"There is a tendency now to try to rush technology into general release before it is really ready. Opportunists are a real concern. My recommen dation is to make any vendor give you a list of real-world users, and get objective advice from someone who doesn't sell the hardware," said Alan Brill, senior managing director of Kroll's information group.

Those who insist on buying into a new system should beware of the novelty factor.

"If somebody sees a new device, they might think that it would be neat to buy it. But building owners should take a step back," said David Aggleton, president of Aggleton & Associates, a security consulting firm. A 25-year veteran of the industry, he is also a member of the International Association of Professional Security Consultants.

Aggleton described how he recently saw an ad on the Internet for a device that detects anthrax spores. It does so, according to the ad, by identifying particles that are the same size of these spores.

"So anything else in the HVAC that is close in size would set off alarms," he said.

Clearly, much of what we are seeing on the market is the result of hasty R & D. Only two months have passed since Sept. 11, and less than that for the anthrax mailings.

"Owners should take a good long look at what these systems can do. You have to be educated before you buy into these things," said Bill Esposito, president of Ambient Labs, an environmental testing company.

In recent weeks Esposito has been fielding plenty of calls from owners concerned about potential anthrax or chemical attacks.

Two new systems have been patented since the attacks, both of which are designed to protect against germ or chemical warfare. One of these systems would actually seal the HVAC system of a building in the event that dangerous agents are detected. The agents would be isolated by what are essentially plastic bags in the vents.

Esposito, who is an expert on how biological agents can spread through a building's HVAC, cautioned owners that "there are limits with these systems."

"You have to look at the detection methods," he said, in order to qualify how effective the system really is.

One weak link in building security is fraudulent ID's. Many office buildings merely look at an ID before allowing someone to pass into the building. But it is simplistic to think that they can detect fake ID's every time.

The concept for a "national identification card" isn't new, but Sept. 11 has convinced many lawmakers that such a network should be created. In a sense, it already exists--with the exception of 14 states that have yet to magnetically encode their licenses. The data stored in a central computer can be cross checked by police, and used to verify someone's identity or record.

Frank Mandelbaum, chairman of Intelli-Check, a publicly held firm that verifies documentation, recently sold his device to the Pentagon.

"This device can scan a fake license and tell then operator that it's a fake," said Mandelbaum, who owns the patent on the technology.

Vornado bought Intelli-Check for one of its Manhattan office buildings, One Penn Plaza. Mandelbaum said that other commercial owners in Manhattan have shown an interest in his product.