Original timber stairwell doors in historic masonry apartment buildings of architectural heritage value can be found in the larger cities of Norway. In Oslo, there are around 4000 such buildings, of which many still hold preserved original stairwell doors. The doors often have glass with decorative patterns in the upper parts, and timber panels on the lower part. Old residential buildings are vulnerable to fire due to the building construction and need fire protection upgrades. The stairwell doors are critical elements to prevent fire spread and to keep evacuation routes safe, so their function and condition are important to the level of fire protection in the building. The research work in this paper aims to find retrofit methods for upgrading the fire resistance of these types of doors so they maintain their integrity and insulating properties for up to 30 minutes, at the same time as they maintain their architectural expression. The upgrades must be as little intrusive and destructive as possible. Intermediate scale tests were carried out in a fire resistance test furnace, using different door configurations. The tests lasted between 30 minutes and 42 minutes, with a thermal exposure from the standard time/temperature curve described in EN 1363–1. The results from the tests showed that 40 mm thick laminated wood could withstand up to 30 minutes of fire exposure, thin timber panels could be upgraded using stone wool and robust gypsum boards type R, and that fire-resistant glass could be mounted on the inside of the original glass in different ways. Visual observations indicate that adding smoke seals inside the door leaf are effective for stopping cold and hot smoke. The solutions presented enables the preservation of the original doors’ architectural design, their historical values and aesthetic character. 

Gamle tredører kan være et av de svakere punktene med hensyn til brannmotstand leilighetsbygg. Denne veilederen foreslår hvordan glass, platekledninger, tetningslister, dørkarmer, lås og beslag kan monteres for at døren kan oppnå en forventet brannmotstand på ca. 30 minutter (tilsvarende som hvis døren ble brannmotstandstestet). Den eneste tiltenkte bruken av denne veilederen er når bytte av dør på grunn av antikvariske hensyn ikke er mulig eller ønskelig. Denne typen gamle dører har typisk en tykkelse på 40-50 mm, med glass i øvre del og en tynnere trefylling i nedre del. Av antikvariske hensyn bør inngrepene på dørene v re minst mulig inngripende og mest mulig reversible. Det ble utført totalt fire branntester, med to små dørmodeller i hver test. Ulike løsninger for montering av brannsikkert glass, gipsplater og tettelister ble testet. Hovedkonklusjonene fra branntestene er: • Glass må ha minimum brannmotstand på 30 minutter (integritet og isolasjon) og være forsvarlig testet med stålrammer eller stålvinkler • Tynnere deler av døren som trefyllinger kan oppgraderes med steinull og 12,5 mm robust gipsplate type R • Rundt dørbladet skal det monteres både gummilist og ekspanderende list • Spalten mellom dørkarm og vegg skal tettes med steinull og branntettemasse

This report contains measurements, observations, and results from 30 experiments with fire in the cavity between the wood cladding and the wind barrier. The experiments were performed at RISE Fire Research's laboratory in Trondheim in 2021. The main focus of the study is on fire inside the cavity between the wind barrier and the cladding. The purpose has been to investigate how different parameters, such as material use and geometry, affect the fire in this cavity. This test series is done by using varying combinations of royal oil-treated and untreated cladding of pine with wind barriers of two different reaction to fire classifications and two different lathing types in the various experiments The various experimental setups have been done in a way that is meant to represent typical constructions in Norwegian houses with wooden cladding. All walls were flat, with cladding without gaps or openings and without internal corners, extruding parts, doors, windows, or other penetrations. In most experiments, measures were taken to shield the outside of the cladding from exposure to the initial fire. In several experiments, however, the fire also established itself on the outside of the cladding after it had burned through the cladding from the inside. Large-scale experiments have also been carried out, where both the cavity and the front of the cladding were exposed to the initial fire. The experiments' results show that the use of royal oil-treated cladding had no statistically significant effect on how the fire in the cavity spread. The results indicate that the use of the used wind barrier with reaction to fire classification F lead to faster flame spread and temperature rise than the used wind barrier with fire classification A2 did, but this is not statistically significant and may be due to random variations. Experiments with vertical lathing showed faster temperature rise in the cavity than experiments with cross-lathing. This means that the heat spreads faster upwards in the cavity when it forms continuous vertical channels than where the cavity is connected both horizontally and vertically between the cross-lathing. In the cavity with cross-lathing, on the other hand, the heat and fire spread to a greater extent laterally than in the cavity with only vertical lathing. The fire in the cavity was in many of the experiments limited by oxygen supply. This shows that the supply of air in the cavity can be as crucial for delimiting the fire spread as the fire properties of the materials inside the cavity. When the cavity fire is delimited by the oxygen supply, higher amounts of combustible gases will be formed in the smoke. This can cause the fire to spread to other places if this gas can be re-ignited.

Older wooden doors can be one of the weaker points with regards to fire resistance in apartment buildings. This guideline proposes how glass, protective boards, sealing lists, hardware and door frames can be mounted to the door to be expected to achieve a fire resistance of approximately 30 minutes (as if the door would be fire resistance tested). The only intended use of this guideline is when changing the door due to antiquarian reasons is not possible or desirable. These types of older doors typically have a thickness of 40-50 mm, with glass on the upper part and a thinner wooden door panel on the lower part. For antiquary reasons, the interventions on the doors should be as little intrusive and as reversible as possible. A total number of four fire tests were performed, with two small door models in each test. Different solutions for mounting of fire resistant glass, gypsum boards and glazing lists were tested. The main conclusions from the fire tests are: Glass must have a minimum fire resistance rating of 30 minutes (integrity and insulation) and be securely fastened with steel frames or steel angles Thinner parts like fielded wooden panels can be upgraded with stone wool and 12.5 mm robust gypsum boards Both intumescent strips and silicone gaskets must be mounted around the door leaf The gap between the door frame and the wall must be sealed using stone wool and fire sealant

This report presents the four large-scale fire tests performed within the FIRENWOOD project. The aim of the tests was to verify the improved fire design models for the I-joists and crosslaminated timber. The results of the loaded floor test with cross-laminated timber were also compared with results from an unloaded model-scale test with similar lamella thicknesses and adhesive. The aim of the compartment fire test was to study the behaviour of I-joists in physically based fire compared to the behaviour in standard fire. The second aim was to compare the fire behaviour of the compartment made of timber frame assemblies with I-joists and the previously performed similar compartments made with CLT. All large-scale tests reported here were performed with engineered wood structures using adhesive No.9