Lucy Clarkbiling
BBC News
A chimney was installed in the Sistine Chapel ahead of the Pope election.
As the Catholic Church elects a new Pope, the world is seeing the rise of smoke from a small chimney above the Sistine Chapel, not press conferences or social media posts.
If the smoke is black, a new Pope is not chosen. If it is white, a decision was made: Habemus Papam – we have a Pope. It’s a high-drama and will be broadcast live to millions.
But what viewers aren’t seeing is the hidden complexity of ceremonies that centuries ago. Carefully constructed chimneys, engineering stoves, and accurate chemical recipes are designed so that each part is painstakingly enough to send a clear message.
Experts told the BBC that the process requires “two custom fireworks,” smoke test rehearsals and Vatican firefighters for standby. It is meticulously organized by a team of engineers and church officials working together.
Reuters
Pope Francis passed away on Easter Monday, 88, and as his funeral was over, attention was drawn to Conclave, a private meeting in which the new Pope was chosen.
The Vatican confirmed that the Cardsals will meet at St. Peter’s Basilica on May 7th to celebrate a special Mass before gathering within the Sistine Chapel where complex voting begins.
The Cardinal’s paper-burning tradition dates back to the 15th century, and became part of Conclave rituals aimed at ensuring transparency and preventing tampering, particularly after the delays in previous pope elections led to public frustration and anxiety.
Over time, the Vatican began using smoke as a way to communicate with the outside world while maintaining strict confidentiality of the vote.
And today, despite countless advances in communication, the Vatican has chosen to maintain its tradition.
“Since ancient times, people have seen the rise of biblical animal and grain sacrifice, or the burning incense of traditions – as a form of human communication with God,” Candida Moss, professor of theology at the University of Birmingham, told the BBC.
“In Catholic tradition, prayer “ascends” to God. The use of smoke evokes these religious rituals and the aesthetics of wonder and mystery that accompany them. ”
Professor Moss also says that rising smoke allows people to gather in St. Peter Square and “feel like it’s contained.”
The reason is symbolic, but real-world engineering is required to make it work in the 21st century.
EPA
Within the Systin Chapel, two stoves are temporarily specially installed for conclaves. One generates smoke signals, one for combustion.
Both stoves are connected to a small flue that leads outward through the roof of the chapel, pipes within the chimney that allow smoke to escape. On Friday, firefighters were seen on the roof, carefully securing the top of the chimney, and workers set up scaffolding to build the stove.
Built over 500 years ago, the Sistine Chapel features one of the most famous ceilings in the world. It is decorated with Michelangelo frescoes and is not designed accurately for smoke signals, so the chimney must be installed carefully and safely.
It’s a complicated process. The technician can use existing openings or create temporary hatches. This hatch is usually inserted with metal flues, such as iron or steel. The pipe runs outward from the stove and appears through a tiled roof above St. Peter’s Square.
All joints are sealed and all components are tested to prevent leaks. The specialists will rehearse smoke inspections before the conclave begins, ensuring that the chimney draw works in real time. Even Vatican firefighters are involved. In the event of a malfunction, it will be in standby.
“This is a very accurate process. If one thing goes wrong, it’s not just a technical failure. It’s an international incident,” Kevin Farram, a structural engineer who worked on the estate’s wealth, told the BBC. “It’s not like putting pipes in a pizza oven. Every part of the system needs to be installed without any damage.”
This setup will be built a few days before the Cardinals arrive and will be demolished once the Pope is selected.
Reuters
Vatican engineers use combinations of compounds to ensure the signal is visible.
“What they’re essentially building here are two custom fireworks,” Professor Mark Roach, director of Chemical and Biochemistry at Hull University, told the BBC.
“In the case of black smoke, a mixture of potassium perchlorate, anthracene and sulfur is burned. It produces thick, dark smoke.
“For white smoke, a combination of potassium chlorate, lactose and pine rosin is used.
“In the past, they tried to burn wet straws to create dark and dry straws and bright smoke, which can sometimes look grey, causing some confusion.”
He explained that these chemicals were “pre-packaged in cartridges and ignited electronically,” so there is no ambiguity.
The addition of Berlinging – introduced during the election of Pope Benedict XVI – now serves as a confirmation and is used along with smoke signals.
Over the years, there have been suggestions for modernizing the system: colored lights, digital alerts, or even aired votes. But for the Vatican, rituals are more than just a communication tool. It is a moment of continuity with centuries of tradition.
“It’s about tradition and secrets, but there’s also a real theological weight,” Professor Moss said.
“Plus “Catholic Church” and “Temporary” are far from synonymous. Innovation is almost the opposite of rituals. ”
EPA
Firefighters installed the chimney on May 2nd.
