Thousands of men and women who work for some of the city’s most luxurious residences plan to turn Park Avenue in Manhattan “into a sea of purple and gold” — the colors of their union — on Wednesday afternoon.

The goal of the demonstration is to bring attention to their efforts to secure “a strong contract” in negotiations between the union, SEIU 32BJ, and property owners represented by the Realty Advisory Board on Labor Relations. Union members will also be voting whether to delegate the power to call a strike their negotiating committee if talks break down by the time their current contract expires on April 20.

So far, negotiations have been going smoothly but contracts have often have been settled in last-minute sessions. Here’s what you need to know.

How did we get here?

Every four years, the union and property owners begin a series of negotiations to hammer out a new contract. The last time it happened, in 2010, the talks went down to the wire, but the two sides ultimately came to an agreement that provided a 10 percent wage increase over four years to the workers. The union also agreed to work toward cutting health care costs and claims it did save property owners millions by switching health plans twice.

Why should New Yorkers care?

The possibility of some 30,000 porters, doormen and superintendents represented by the union walking off the job has residents in about 3,000 buildings on edge since they rely on building staff for everything from taking out the trash to holding packages. Buildings that could be affected include condos, co-ops and rentals.

The union says its members have decent paying jobs that barely allow their members to provide for their families in an increasingly unaffordable city. It has launched a “Making NY Home” campaign in coordination with contract talks that plays into current political discourse around income inequality in the city.

How much does a building worker get compensated?

The average doorman makes about $44,000 a year in salary, plus health and retirement benefits, the union says. The Realty Advisory Board says property owners pay an average $77,000 a year for each porter or doorman. Other jobs are compensated differently.

What is at the core of the negotiations?

Both the union and the Realty Advisory Board say they are fighting to maintain middle-class jobs. Wages, health care and retirement are all up for negotiation.

The union wants to see its members get a cost of living wage increase, arguing that it’s more difficult than ever before for them to make ends meet in price New York City. It also wants health and retirement benefits kept at their current level.

The Realty Advisory Board calls building service work a “great middle class occupation.” It posted a list of points on its website about the negotiations, striking an optimistic tone but also making it clear that it is starting with a baseline that it provides great value and benefit to building workers. 

How could a strike affect people who live in these buildings?

A strike could make life a mess for thousands of residents, complicating plans for moves as well as deliveries. Doormen and doorwomen often serve as quasi-security; accept packages when residents aren’t home; and even run the service elevators. Handymen and women basically keep the air conditioning working; porters take out the trash. None of that will be happening if workers walk out. And residents shouldn't expect a break on their rent.

What is the timeline for negotiations?

As of Wednesday, the two sides have met for three negotiations. The next discussion is set for April 8, when the union says wage and economics will be discussed — meaning negotiations could get rocky from then on. The contract expires on April 20, when the union could call a strike.