Functional safety (FuSa) standards such as IEC 61508 and ISO 26262 advocate a particularly stringent Requirements engineering (RE) where safety requirements must be structured in an hierarchical manner and specified in accordance with the system architecture. In contrast to the stringent RE in FuSa standards, according to previous studies, RE in industry is in general of poor quality. Contracts theory has been previously shown to be suitable for supporting such a stringent RE effort; this support has also been implemented in tools. However, to use these contract-based tools, requirements must be formalized, which is a major challenge in industry. Therefore, to support current industrial RE practice and the stringent RE in FuSa standards, it is shown how support in a specification tool can be provided even when requirements, and also architectures, are not formalized. This is achieved by enforcing syntactic, yet formal, conditions in contracts theory. Furthermore, a validating industrial case study is presented where the proposed support is shown to be fully applicable in an industrial setting.